PURPOSE: To improve a pull-down characteristic which is the lowering speed of crank chamber temp. at the time of starting with a simple and low-cost structure by forming a pressure regulating means in a crank chamber with various mechanisms which are controlled in accordance with the pressure and temp. of a sucked refrigerant respectively.

CONSTITUTION: A pressure regulating means 9 regulates pressure in a crank chamber 2 to control the inclination angle of a swash plate 6 to a rotary main axis 4. And, a piston 8 is reciprocated in a cylinder 31 via a swinging board 7, to vary the capacity of a discharged fluid from a suction chamber 15 to a discharge chamber 16. In this case, the pressure regulating means 9 consists of a mechanism 91 which connectingly controls the chambers 2, 15 in accordance with the pressure of the suction chambers 15 and a mechanism 95 which connectingly control the chambers 2, 15 in accordance with temp. change of a suction gas. And, when a compressed refrigerant is overheated as at the time of pull-down, priority is given to the control of one controlling mechanism 95, to prevent a compressor from continuing to operate with its capacity being reduced even when a suction pressure is lowered to a variable capacity set value.