To improve the physiological reliability in the case of in-vivo feeding blood with a pump.

A linear pump 10 includes a housing 22 having a bore 22a, an inlet 22b and an outlet 22c which are spaced in an axial direction. A first check valve 24a is unified with the housing 22 so as to control the flow of fluid passing through the bore. A piston 26 is fitted to the same shaft with the housing bore so as to move in the axial direction in the housing bore, and includes a piston bore 26a, and an inlet 26b and an outlet 26c which are spaced in the axial direction. A second check valve 24b is unified with the piston so as to control the flow of the fluid passing through the piston bore. Also, the pump consists of a linear motor consisting of a plurality of stator drive coils 28a which are arranged inside the housing 22 and are adjacent to the axial direction, and permanent magnet rings 28b arranged inside the piston.