To absorb pulsation flow without requiring large capacity by providing pulsation smoothening damper members capable of changing volume by pressure variation of fluid on the discharge side of a reciprocating type pump sucking and discharging fluid by turning force of an armature.

When electric current is supplied to a brush, an armature shaft 5a is rotated, a rotor 19 for pressing plunger fitted to a cam 5a2 is rotated, first and second plungers 31, 51 are begun to reciprocate in first and second cylinder blocks 30, 50, and fluid is passed in first and second pulsation smoothening damper members 8, 9 through second and fifth communicating pipe lines 11b2, 11c2. At this time, pulsation is generated in the fluid, and when the fluid is passed through, the first and second pulsation smoothening damper members 8, 9 are expanded at low pulsation pressure and contracted at high pulsation pressure, so as to repeat expansion and contraction, the fluid passing though the first and second pulsation smoothening dampers 8, 9 are passed through first and second orifices, and smoothend and fed to first and second discharge pipe lines 11f, 11i.