To sufficiently improve compressing efficiency while satisfying demands such as miniaturization and cost reduction.

A cylinder 11 and a piston 12 are formed into bottomed cylindrical shapes, the piston 12 is fitted from a bottom side of the cylinder 11, and reciprocated by a driving force from a linear motor 20. By applying this constitution where the cylinder 11 is recessed, a device can be miniaturized. Further a plurality of disc-shaped plate springs 28 are mounted. The piston 12 is fitted to inner sides of the plate springs 28, and its outer peripheral side is fixed to a housing 29. Whereby the resonance frequency of the piston 12 is increased, the plate springs 28 act as radiation fins to efficiently release the heat, and the compression efficiency can be improved.