[Claim 1] A fuel injection valve, comprising:
a valve seat having a seat surface inclined in a direction of approaching an axial line of the fuel injection valve to a downstream side of a flow of fuel;
a valve body, which includes a ball, is displaceable between a valve closed position at which the ball is brought into contact with the seat surface and a valve open position at which the ball is separated away from the seat surface, and is configured to open and close a gap fuel passage formed between the ball and the seat surface; and
an injection-hole plate, which has a plurality of injection holes, and is arranged on the downstream side of the flow of fuel with respect to the valve seat,
wherein the injection-hole plate has a plate opposing surface that is opposed to the valve seat,
wherein the plate opposing surface has openings of the plurality of injection holes as injection hole inlets,
wherein the plurality of injection holes are inclined in a direction of being separated away from the axial line from the injection hole inlets to the downstream side of the flow of fuel,
wherein the seat surface has a contact portion with which the ball is held in contact when the valve body is located at the valve closed position, and
wherein, when a position of a downstream end portion of the

seat surface is set as a seat outlet position, and a position of the contact portion of the seat surface is set as a seat contact position, the injection hole inlets are each formed in a range in which the gap fuel passage directly faces the plate opposing surface from the seat outlet position when the valve body is located at the valve open position, and a sectional area of the gap fuel passage at the seat outlet position is 1.3 times or less of a sectional area of the gap fuel passage at the seat contact position when the valve body is located at the valve open position.
[Claim 2] The fuel injection valve according to claim 1, wherein, when a position of an upstream end portion of the seat surface is set as a seat inlet position, a length from the seat inlet position to the seat contact position in the gap fuel passage is larger than a length from the seat contact position to the seat outlet position in the gap fuel passage.
[Claim 3] The fuel injection valve according to claim 1 or 2,
wherein a passage outlet of the gap fuel passage is formed at the seat outlet position, and
wherein, when the valve body is located at the valve open position, a tangential line to the ball at the passage outlet of the gap fuel passage and the axial line intersect with each other in a space between the ball and the plate opposing surface.

[Claim 4] The fuel injection valve according to any one of claims 1 to 3, wherein, when the valve body is located at the valve closed position, in a direction along an axial line of each of the injection holes, a distance between each of the injection hole inlets and the ball is smaller than a length of the each of the injection holes.