Patent ID: 7908733

Claim:
A method for manufacturing an injection hole member formed with an injection hole for injecting fluid, the method comprising: an injection hole forming step of forming the injection hole so that an axis of the injection hole in an injection direction is inclined with respect to an axis of a base material of the injection hole member in its thickness direction, and a concave portion forming step of forming a concave portion caving in radially outward from an inner peripheral surface providing the injection hole in an edge of a downstream end opening of the injection hole, wherein the injection hole is formed so that one of two injection hole intersection lines between a virtual plane, which includes the axis of the injection hole and is perpendicular to the base material, and the inner peripheral surface of the injection hole provides an acute angle with a downstream end plane of the injection hole and the other injection hole intersection line provides a blunt angle with the downstream end plane of the injection hole, and the concave portion is formed in the edge of the downstream end opening of the injection hole only on a side where the acute angle is provided between the injection hole intersection line and the downstream end plane of the injection hole, said concave portion being formed by applying brush grinding to the edge of the downstream end opening of the injection hole only on the side where the acute angle is provided.