To provide an electromagnetic piston pump reducing the axial length of the electromagnetic piston pump and preventing fluid sucked once from undesirably flowing reversely to an outside of a suction port.

The electromagnetic piston pump 1 includes: a casing 3 including the suction port 4 and a discharge port 2; and, in the casing 3, a hollow piston 12 with a suction and discharge valve 11, an exciting coil 5 wound around a bobbin 8, a soft iron flange 6 comprising a flange projection part 61 and a flange base part 62, a support shaft 9 reciprocatably supporting the piston 12, a permanent magnet 7 attached to one end of the support shaft 9, a piston shaft 10 fitted to another end of the support shaft 9, conical shape coil springs 15, 18 elastically supporting the piston 12, a holding plate 16 including a plurality of projection parts 161 and fixed on the piston 12, a suction chamber 13 sucking fluid from the suction port 4, and a pump chamber 17 discharging the fluid from the discharge port 2. The suction port 4 is blocked by the piston 12 at an early stage of expansion stroke.