To control the performance of a compressor by controlling the amount of circulation of refregerant through regulation of opening of a suction valve in the compressor.

This compressor is provided with a suction valve 11 composed of a suction lead 14 having a magnet 22 fixed in a face corresponding to a suction hole 12, an electromagnet 23 having a tip 23a facing the lead 14 at an opposite position through the lead 14 and the hole 12 or in the hole 12, a suction valve opening control means 25 sending a signal after determinating the amount of opening of the valve 11, and a voltage control means 26 regulating a supplied voltage as well as supplying a current to the electromagnet 23 according to a command from the means 25. With the constitution, a supplied voltage to the electromagnet 23 is controlled so as to control the lift-up amount of the lead 14 for controlling the passing amount of refregerant.