A compression chamber includes the compression chamber partitioning member, an intermediate pressure chamber guides an intermediate pressure working fluid before injection to the compression chamber, and the intermediate pressure chamber and the compression chamber face each other with a compression chamber partitioning member interposed between the intermediate pressure chamber and the compression chamber. Further, the intermediate pressure chamber includes an intermediate pressure chamber inlet through which an intermediate pressure working fluid flows, an injection port inlet of an injection port through which the intermediate pressure working fluid is injected into the compression chamber, and a liquid reservoir formed at a position below the intermediate pressure chamber inlet, and the liquid reservoir is formed by the compression chamber partitioning member.