An expander-integrated compressor (5A) has a compression mechanism (21) for compressing a refrigerant and an expansion mechanism (22) for expanding the refrigerant. The compression mechanism (21) is located above the expansion mechanism (22) inside a closed casing (10) and shares a rotating shaft (36) with the expansion mechanism (22). An oil pump (37) is provided at the lower end of the rotating shaft (36). The oil pump (37) is immersed in oil in an oil reservoir (15). Usually, the oil is placed in the oil reservoir (15) in such a manner that the oil level (OL) is located above a lower end portion (34e) of a vane (34a) of a first expansion section (30a). More preferably, the oil is placed in such a manner that the expansion mechanism (22) is immersed in the oil. An oil supply passage (38) for guiding the oil to the compression mechanism (21) is formed inside the rotating shaft (36). A suction port (37a) of the oil pump (37) is provided below the lower end portion (34e) of the vane (34a).