1. A compound represented by General Formula [1] or a salt thereof:
in the formula, R1 represents a benzothiazolyl group which may be substituted (in which a carbon atom constituting the 6-membered ring of the benzothiazolyl group of R1 is bonded to the nitrogen atom of the pyridone ring);
R2 represents a C2-6 alkenyl group which may be substituted, a C2-6 alkynyl group which may be substituted, a C3-8 cycloalkyl group which may be substituted, an aryl group which may be substituted, or a heterocyclic group which may be substituted; and
R3 represents a hydrogen atom or a carboxy-protecting group.
2. The compound or a salt thereof according to claim 1,
wherein the compound is a compound represented by General Formula [1-1]:
in the formula, m Ral's are each independently the same as or different from each other, and represent a halogen atom, a cyano group, a nitro group, a C1-6 alkyl group which may be substituted, a C1-6 alkoxy group which may be substituted, a C1-6 alkylamino group which may be substituted, a di(Ci-6 alkyl)amino group which may be substituted, a carbamoyl group which may be substituted, a sulfamoyl group which may be substituted, or a carboxyl group which may be protected;
Rbl represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, a C1-6 alkyl group which may be substituted, a C1-6 alkoxy group which may be substituted, a C1-6 alkylamino group which may be substituted, a di(Ci-6 alkyl)amino group which may be substituted, an acylamino group which may be substituted, a carbamoyl group which may be substituted, a sulfamoyl group which may be substituted, a heterocyclic group which may be

substituted, or a carboxyl group which may be protected;
R2 represents a C2-6 alkenyl group which may be substituted, a C2-6 alkynyl group which may be substituted, a C3-8 cycloalkyl group which may be substituted, an aryl group which may be substituted, or a heterocyclic group which may be substituted;
R3 represents a hydrogen atom or a carboxy-protecting group; and
m represents an integer of 0 to 3.
3. The compound or a salt thereof according to claim 2,
wherein m Ral,s are each independently the same as or different from each other, and are each a halogen atom, a C1-6 alkyl group which may be substituted, or a C1-6 alkoxy group which may be substituted; and
m is an integer of 0 or 1.
4. The compound or a salt thereof according to claim 2 or 3,
wherein Rbl is a hydrogen atom, a halogen atom, a C1-6 alkyl group which may be substituted, a C1-6 alkoxy group which may be substituted, a C1-6 alkylamino group which may be substituted, a di(Ci-6 alkyl)amino group which may be substituted, or a heterocyclic group which may be substituted.
5. The compound or a salt thereof according to any one of claims 1 to 4,
wherein R2 is a phenyl group which may be substituted, a thienyl group which may be substituted, a thiazolyl group which may be substituted, or a benzoxazinyl group which may be substituted.
6. The compound or a salt thereof according to any one of claims 1 to 4,
wherein R2 is a phenyl group which may have one or more substituents selected from the substiruent group Ai, a thienyl group which may have one or more substituents selected from the substiruent group Ai, a thiazolyl group which may have one or more substituents selected from the substiruent group Ai, or a benzoxazinyl group represented by General

substituted, an acyl group which may be substituted, a Ci-6 alkylsulfonyl group which may be substituted, or an arylsulfonyl group which may be substituted;
Rb2 represents a hydrogen atom, a Ci-6 alkyl group which may be substituted, an aryl group which may be substituted, an acyl group which may be substituted, a carbamoyl group which may be substituted, a sulfamoyl group which may be substituted, a heterocyclic group which may be substituted, or a carboxyl group which may be protected; or
Ra2 and Rb2 may be combined with an atom to which they are bonded to form a 5-membered heterocycle which may be substituted or a 6-membered heterocycle which may be substituted; and * represents a bonding position,
in which the substituent group Ai consists of groups represented by:
a halogen atom,
a cyano group,
a nitro group,
a Ci-6 alkyl group which may have one or more substituents selected from the substituent group A2,
an aryl group which may have one or more substituents selected from the substituent group A2,
a Ci-6 alkoxy group which may have one or more substituents selected from the substituent group A2,
a Ci-6 alkylamino group which may have one or more substituents selected from the substituent group A2,
a di(Ci-6 alkyl)amino group which may have one or more substituents selected from the substituent group A2,
a carbamoyl group which may have one or more substituents selected from the substituent group A2,
a sulfamoyl group which may have one or more substituents selected from the substituent group A2,
a heterocyclic group which may have one or more substituents selected from the substituent group A2, and
a carboxyl group which may be protected;
the substituent group A2 consists of groups represented by:
a halogen atom,
a cyano group,
a nitro group,

a Ci-6 alkyl group which may have one or more substituents selected from the substituent group A3,
an aryl group which may have one or more substituents selected from the substituent group A3,
a C1-6 alkoxy group which may have one or more substituents selected from the substituent group A3,
a C1-6 alkylamino group which may have one or more substituents selected from the substituent group A3,
a di(Ci-6 alkyl)amino group which may have one or more substituents selected from the substituent group A3,
an acylamino group which may have one or more substituents selected from the substituent group A3,
a carbamoyl group which may have one or more substituents selected from the substituent group A3,
a sulfamoyl group which may have one or more substituents selected from the substituent group A3,
a heterocyclic group which may have one or more substituents selected from the substituent group A3, and
a carboxyl group which may be protected;
the substituent group A3 consists of groups represented by:
a halogen atom,
a cyano group,
a nitro group,
a C1-6 alkyl group which may have one or more substituents selected from the substituent group A4,
an aryl group which may have one or more substituents selected from the substituent group A4,
a C1-6 alkoxy group which may have one or more substituents selected from the substituent group A4,
a C1-6 alkylamino group which may have one or more substituents selected from the substituent group A4,
a di(Ci-6 alkyl)amino group which may have one or more substituents selected from the substituent group A4,
a carbamoyl group which may have one or more substituents selected from the

substituent group A4,
a sulfamoyl group which may have one or more substituents selected from the substituent group A4,
a heterocyclic group which may have one or more substituents selected from the substituent group A4, and
a carboxyl group which may be protected; and
the substituent group A4 consists of groups represented by:
a halogen atom,
a cyano group,
a nitro group,
a C1-6 alkyl group,
an aryl group,
a C1-6 alkoxy group,
a C1-6 alkylamino group,
a di(Ci-6 alkyl)amino group,
a carbamoyl group,
a sulfamoyl group,
a heterocyclic group, and
a carboxyl group.
7. The compound or a salt thereof according to claim 6,
wherein the substituent group Ai is:
a halogen atom,
a cyano group,
a C1-6 alkyl group which may have one or more substituents selected from the substituent group A2,
a C1-6 alkoxy group which may have one or more substituents selected from the substituent group A2,
a C1-6 alkylamino group which may have one or more substituents selected from the substituent group A2,
a di(Ci-6 alkyl)amino group which may have one or more substituents selected from the substituent group A2, or
a heterocyclic group which may have one or more substituents selected from the substituent group A2;

the substituent group A2 is:
a C1-6 alkoxy group which may have one or more substituents selected from the substituent group A3,
an acylamino group which may have one or more substituents selected from the substituent group A3, or
a carbamoyl group which may have one or more substituents selected from the substituent group A3;
the substituent group A3 is:
a C1-6 alkyl group which may have one or more substituents selected from the substituent group A4,
an aryl group which may have one or more substituents selected from the substituent group A4, or
a C1-6 alkoxy group which may have one or more substituents selected from the substituent group A4; and
the substituent group A4 is:
a halogen atom,
a cyano group, or
a C1-6 alkyl group.
8. The compound or a salt thereof according to claim 6,
wherein the substituent group Ai is:
a halogen atom,
a cyano group,
a nitro group,
a C1-6 alkyl group which may have one or more substituents selected from the substituent group A2,
an aryl group which may have one or more substituents selected from the substituent group A2,
a C1-6 alkoxy group which may have one or more substituents selected from the substituent group A2,
a C1-6 alkylamino group which may have one or more substituents selected from the substituent group A2,
a di(Ci-6 alkyl)amino group which may have one or more substituents selected from the substituent group A2,

a carbamoyl group which may nave one or more substituents selected from the substituent group A2,
a sulfamoyl group which may have one or more substituents selected from the substituent group A2,
a heterocyclic group which may have one or more substituents selected from the substituent group A2, or
a carboxyl group which may be protected; and
the substituent group A2 is:
a halogen atom,
a cyano group,
a nitro group,
a C1-6 alkyl group,
an aryl group,
a C1-6 alkoxy group,
a C1-6 alkylamino group,
a di(Ci-6 alkyl)amino group,
a carbamoyl group,
a sulfamoyl group,
a heterocyclic group, or
a carboxyl group.
9. The compound or a salt thereof according to claim 6, wherein the substituent group Ai is: a halogen atom, a cyano group, a nitro group, a C1-6 alkyl group, an aryl group, a C1-6 alkoxy group, a C1-6 alkylamino group, a di(Ci-6 alkyl)amino group, a carbamoyl group, a sulfamoyl group, a heterocyclic group, or

a carboxyl group.
10. The compound or a salt thereof according to claim 6,
wherein Ra2 is a hydrogen atom or a Ci-6 alkyl group which may be substituted; Rb2 is a hydrogen atom; or
Ra2 and Rb2 may be combined with an atom to which they are bonded to form a 5-membered heterocycle which may be substituted.
11. A pharmaceutical composition comprising:
the compound or a salt thereof according to any one of claims 1 to 10.
12. An anti-hepatitis B virus agent comprising:
the compound or a salt thereof according to any one of claims 1 to 10.
13. A production inhibitor of DNA of a hepatitis B virus comprising:
the compound or a salt thereof according to any one of claims 1 to 10.
14. A production or secretion inhibitor of a hepatitis B surface antigen comprising:
the compound or a salt thereof according to any one of claims 1 to 10.