Lifetime required of mobile-use fuel cells is secured and prolonged, stabilized pump performance is maintained by preventing bearing seizure and abnormal wear. The shaft (101) of a pump mechanism section (100) and the shaft (201) of a motor section (200) are integrated, and the shafts (101, 201) are supported by two or more ball bearings disposed in the pump mechanism section (100), thereby making it possible to fill grease in the closed spaces of the ball bearings (300), and secure a sufficient lifetime basically with almost no possibility of the grease leaking out, even if it is used at a relatively high environmental temperature.