Fuel Pump

The present invention provides a fuel pump capable of suppressing sticking of a plunger. The fuel pump of the present invention includes a plunger that reciprocates, a cylinder in which a guide hole that guides the reciprocating motion of the plunger extends in the axial direction, and a pump body that holds the cylinder . The pump body 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 . The cylinder includes a press-fitting portion press-fitted into the inner peripheral surface of the cylinder insertion hole , and a groove formed at a position corresponding to the press-fitting portion on the inner peripheral surface of the guide hole