To provide a vacuum cooling system for cooling a cooling object in a short time by efficiently utilizing a characteristic of a centrifugal or diagonal flow compression device, and reducing power consumption necessary for operation over a whole temperature range.

Gas in a housing chamber 2a for housing water containing material or water as the cooling object F is sucked by at least one of variable speed centrifugal compression devices 11, 12 and a variable speed diagonal flow compression device. A value corresponding to at least one of pressures in the housing chamber 2a and a temperature of the cooling object F housed in the housing chamber 2a is detected by sensors 7, 8. A control device 16 controls rotation speeds of impellers 11a, 12a of the compression devices 11, 12 in response to a detected value increased as pressure in the housing chamber 2a decreases.