To prevent a depositing material from staying and accumulating in the liquid compartment of a pump even if transfer liquid containing a depositing material such as slurry is used.

A barrier 7 such as an axially reciprocating bellows, diaphragm or the like is provided inside the pump body 1 so as to form a liquid compartment 9 between it and the inner wall 4a of the pump body 1. A suction opening 18 and a discharge opening 19 are provided on the inner wall 4a. A process to suck liquid and a process to discharge the liquid are alternately carried out by reciprocation of the barrier 7. The suction opening 18 is to spout out sucked liquid toward the circumferential wall 9a in the liquid compartment 9 by providing it on the side of the protruded tip part of a suction check valve 20 fixed so as to protrude in the liquid compartment 9 from the inner wall 4a of the pump body 1. Since the inside of the liquid compartment 9 is stirred by this circling flow, a depositing material can be prevented from depositing and condensing in the liquid compartment 9 by reducing holdup of the liquid in the liquid compartment 9.