To prevent seizure of a compressor body in the cold, by installing a branched passage formed by branching a pipe line, mounting a switch valve on the branched passage, and connecting the other edge of the branched passage with an inlet port of the compressor body.

When a start switch is located on a starting position, an electromagnetic valve 19 mounted on a branched passage 13a, is opened, a compressor is started, and the outside air is sucked into the compressor body 1 through an air cleaner 5. Immediately after the starting, the pressure in a receiver tank 10 is lower than the pressure in a cylinder 2, so that the lubricating oil 7 in the receiver tank 10 is not supplied to the cylinder 2. But an inlet passage 20 is in a condition of the negative pressure, so that the pressure difference is generated between the inside of the receiver tank 10 and the inside of the inlet passage 20, and the lubricating oil is supplied to the inlet passage 20 from the branched passage 13a. Thereby the lubricating oil 7 can be supplied into the compressor body 1 immediately after the starting, and seizure of a sliding part in the compressor body 1, can be prevented.