WE CLAIM:
1. A pack for spinning being a pack that is used for a production process of a fiber and that is provided with a kneading part disposed on a spinneret,
the kneading part comprising:
an introduction plate including a plurality of first introduction holes for introducing a melted polymer; and
a plurality of kneading units including
a supply plate including a plurality of independent supply grooves into which the polymer introduced from the introduction holes flows and one or more supply holes disposed in each of the supply grooves, and
a converging plate including a plurality of converging grooves in which a plurality of grooves into which the polymer supplied from the supply holes flows are intersected and a plurality of second introduction holes disposed in each of the converging grooves, wherein
when the kneading part is divided into virtual regions including an equal area on a face perpendicular to a polymer spinning path direction and separated in parallel with the polymer spinning path direction from an upstream side end to a downstream side end,
the first introduction holes penetrating the introduction plate are formed in each of the divided virtual regions;
each first end of the supply grooves is disposed just below the corresponding first introduction hole or the corresponding second introduction hole, each second end of the supply grooves is disposed in a virtual region different from a virtual region where the first end is disposed, and each of the supply holes is formed in each

second end of the supply grooves;
the converging grooves are disposed in the respective divided virtual regions, each first end of the grooves configuring the converging grooves is disposed just below the corresponding supply hole, and each of the second introduction holes is formed in each second end of the grooves; and
when attention is paid on the supply grooves on an upstream side and the supply grooves on a downstream side communicating with each other through the converging grooves, a second end of at least one supply groove on the downstream side is disposed in a virtual region different from any virtual regions where the first ends of the supply grooves on the upstream side are disposed.
2. The pack for spinning according to claim 1, wherein the virtual regions where the first ends of the supply grooves are disposed are adjacent to the virtual region where the second end is disposed.
3. The pack for spinning according to claim 1 or 2, wherein
a degree of kneading M defined by the following formula:
M = (1 - 1/Dn) x (1 - 1/R) is 0.6 or higher where number of division of the virtual regions is R, number of the first introduction holes and the second introduction holes formed in one of the virtual regions is D, and number of components of the kneading unit is n.
4. A method for producing a fiber, the method comprising
producing a fiber using the pack for spinning according to any one of claims 1 to 3.