PURPOSE: To enable to arrange a compressor and a motor in a single casing, by disposing connecting members for connecting the compressor and the motor to each other around an oscillation plate adapted for driving a piston.

CONSTITUTION: A compressor actuating section 2 in an enclosed casing 1 is composed of a cylinder constituting member 6 having three cylinders 5 disposed with uniform angular intervals from each other, a rotary cam 23 connected to a driving shaft 24 of a motor 4 and having an inclined surface 23a for oscillating an oscillation plate 17, and the oscillation plate 17 shaped substantially in a triangular form which is disposed with some inclination for causing reciprocal movement of pistons 21 in the cylinders 5. Further, connecting members 30, 30' for connecting said cylinder constituting 6 and the motor 4 to each other are disposed respectively between each side 34 of the oscillation plate 17 and the casing 1.