A fuel supply pump includes a housing, a camshaft and a cam ring. The camshaft is rotatably supported in the housing. The cam ring is supported around a cam portion of the camshaft such that the cam ring is rotatable with respect to the cam portion. A washer member is provided between an axial end face of the cam portion and the housing, so that the cam portion and the camshaft is axially aligned. A bearing is circumferentially inserted between the end face of the cam portion and the cam ring. An axial end face of the cam ring defines oil grooves, so that lubricating oil flows from a cam chamber into a gap, which is formed between the cam portion and the bearing. Lubricating oil is sufficiently supplied to the periphery of the cam portion, so that the camshaft can be protected from seizure in the fuel supply pump.