Abstract: A micro pump which employs magnetostrictive or electrostrictive elements as solid drive elements and is capable of self-priming even though its flow rate is increased. In the pump, disk-shaped valve elements respectively having tapered protrusions on one side are used as check valves to reduce weight and made to follow the motion of liquids so as to smoothly open and close. Retainers for regulating the gap h between the valve seats and the valve elements are respectively provided with tapered recesses for guiding the protrusions of the valve elements, whereby the valves are prevented from contacting the retainers, thus undergoing less friction therewith, to ensure smooth opening and closure of the valves. Moreover, ringlike or sheetlike elastic materials are provided on the bottoms of the recesses to improve responsivity in the direction in which the valves are closed.