SUPPLY PUMP

A cam ring of a supply pump revolves around a camshaft without rotating. A tappet reciprocates in a direction perpendicular to the camshaft in response to revolution of the cam ring such that the tappet slides along a cam ring sliding surface. A plunger reciprocates together with the tappet to pressurize and deliver fuel. The cam ring sliding surface is shaped in a convex form that has a curved contour line which is non-circular. A height of an inside of the cam ring sliding surface is higher than a height of a periphery of the cam ring sliding surface. Specifically, an ellipsoidal surface portion is formed at the cam ring sliding surface, and an axial direction of a major axis of the ellipsoidal surface portion is set to coincide with a direction perpendicular to a sliding direction of the cam ring sliding surface.