PURPOSE: To effect capacity control, in which the variation of temperature in a water circulating circuit is reduced, economically by a method wherein a flow rate control unit, opened and closed by the control signal of a controller, and a regulating valve, provided with a bypass unit through which predetermined heat medium flows, are provided between an evaporator and a compressor.

CONSTITUTION: A compressor 1 for a refrigerating cycle and a controller 11, detecting the outlet temperature of fluid cooled by an evaporator 4 connected to a temperature type automatic expansion valve 3 and outputting a control signal by comparing the detected temperature with a set temperature, are provided in the title device. Further, an electrically driven control valve 13, provided with a flow rate regulating unit, connected to the controller 11 and opened and/or closed by the control signal of the controller 11, and a bypass unit, through which predetermined heat medium flows, are provided between the evaporator 4 and the compressor 1. According to such a constitution, capacity control, in which the amount of refrigerant flowing through the bypass unit of the electrically driven control valve 13 is secured, the fluctuation of the outlet temperature of the fluid to be cooled may be restricted and the variation of temperature of a water circulating circuit is reduced, may be effected economically.