Abstract: A fuel injector includes (i) a body including a distal end portion forming an injection port, a diameter reduction portion, and a diameter expansion portion, and (ii) a seal member attached to at least the diameter reduction portion of both the diameter reduction portion and the diameter expansion portion. When the body is inserted into an attachment hole communicating with a combustion chamber of an internal combustion engine, the seal member seals between an inner peripheral surface of the attachment hole and an outer peripheral surface of the body. The seal member includes a first taper portion chamfered and provided at an outer periphery of a distal end portion of the seal member in a case where the distal end portion of the seal member is placed at a position relatively close to the injection port.

Abstract: To provide a fuel supply apparatus capable of preventing seizure of a plunger by preventing deformation of a cylinder caused by attaching attachment parts, and capable of being decreased in size, respective attachment parts of a fuel inlet, a delivery valve and a pressure regulator are threadably attached to a housing on a same cross-sectional plane orthogonal to an axis of a high pressure fuel pump, and imaginary extended regions extending seat surfaces of the housing in a direction of attaching thereof, are disposed outside of an outer peripheral surface of a cylinder. Accordingly, even when the attachment parts push the seat surfaces in threadably attaching the respective attachment parts to the housing, almost no axial forces are exerted on the cylinder. Therefore, an inner peripheral surface of the cylinder can be prevented from being deformed, and a sliding clearance between the cylinder and a plunger is prevented from being reduced in size.