PURPOSE: To reduce the installation height of an accumulator by allowing the side conduit communicating to the cylinder in an accumulator and the space in the lower part of the accumulator to communicate through a thin pipe.

CONSTITUTION: An upper conduit 3 communicating to the low-pressure part in a refrigeration cycle is connected into the upper part of an accumulator 1, and a side conduit 13 which is arranged upwardly in the accumulator 1 and communicates to the inside of the cylinder of a compressor is connected to the side surface in the lower part. A thin pipe 14 for returning oil from the lower space in the accumulator is installed to the side conduit 13. Therefore, the installation height of the accumulator 1 can be reduced in comparison with the case where a conduit connected to a cylinder 7 is installed onto the bottom surface in the lower part of the accumulator 1.