A pump housing supporting a driving shaft has a plurality of cylinder bores extending radially and arranged at substantially regular intervals around an outer periphery of the driving shaft. Each cylinder bore has a plunger fitted therein, which reciprocates in response to a rotation of the driving shaft. An inlet, an inlet valve, an outlet, and an outlet valve are provided for each plunger. Fluid flowing from an inlet port provided in the pump housing flows into each inlet, and moreover, fluid flowing from each outlet passes through an outlet passage and flows into an outlet port provided in the pump housing. The outlet passage has a plurality of communication holes corresponding to the outlet valves. Outlet ends of the communication holes converge on one spot in the pump housing.