An oil—cooled air compressor is provided with: an oil—cooled air compressor for compressing sucked-in air and discharging the compressed air; an oil separator for separating the compressed air and lubricating oil, which are discharged from the air compressor body; an oil cooler for cooling, by outside air, lubricating oil discharged from the oil separator; oil supply pipe passage for supplying lubricating oil, which is discharged from the oil cooler, to a bearing of the air compressor body and to an intermediate section in the process of compression by the air compressor; and an after-cooler for cooling, by outside air, air discharged from the oil separator. The oil-cooled air compressor in which the air compressor, the oil separator, the oil cooler, and the after-cooler are connected to supply high-pressure air to the outside of the compressor is provided with a vapor compression type refrigeration cycle.