To resolve drawbacks of a conventional reciprocating pump and to make the best use of advantages of the reciprocating pump.

This reciprocating pump 10 includes a cylinder 14 provided with a closed inner partition chamber 18. A piston assembly 12 is mounted in the partition chamber to be movable in a reciprocating way in an opposite straight line direction. A linear magnetic driving device 50 generates a linearly moving magnetic field for moving the piston assembly in the opposite straight line direction by a sweep volume. A seal member 17 for dividing the partition chamber into a distribution chamber 20 and a storing chamber 22 is placed between the cylinder 14 and the piston assembly 12. An inlet conduit 30 communicates with the distribution chamber, and an outlet conduit 32 communicates with the outlet conduit 32 to orient a pumped liquid to an outside of the partition chamber, when the piston assembly moves by the sweep volume in a distribution stroke. An energy storing releasing medium communicates with a storage chamber, stores the energy resulted from the piston assembly moving in a direction apart from a distribution end of the partition chamber, and releases the stored energy, when the piston assembly moves toward the distribution end.