Fuel pump

A fuel pump comprising:

• a plunger that reciprocates;
• a cylinder in which a guide hole for guiding a reciprocating motion of the plunger extends in an axial direction;
• and
• a pump body that includes a cylinder insertion hole into which the cylinder is inserted, and a pressurizing chamber that communicates with the cylinder insertion hole and has a volume increased or decreased by the reciprocating motion of the plunger, and holds the cylinder, wherein
• the cylinder includes a press-fitting portion in contact with an inner peripheral surface of the cylinder insertion hole, and a groove formed at a position corresponding to the press-fitting portion on an inner peripheral surface of the guide hole,
• the press-fitting portion is formed in an annular shape continuous in a circumferential direction on the outer peripheral surface of the cylinder,
• the groove is disposed at a position overlapping the press-fitting portion when viewed from the radial direction of the cylinder, and is formed in an annular shape continuous in the circumferential direction on the inner peripheral surface of the cylinder,
• a length of the groove in an axial direction of the cylinder is longer than a length of the press-fitting portion in the axial direction of the cylinder,
• a central portion of the groove coincides with a central portion of the press-fitting portion in the axial direction of the cylinder, and
• the plunger slides on the inner peripheral surface of the guide hole where the groove is not formed.