An expander-integrated compressor 200A includes a closed casing 1, a compression mechanism 2, an expansion mechanism 3, a shaft 5, an
oil pump 6, and a heat insulating structure 30A. The
oil pump 6 is disposed between the compression mechanism 1 and the expansion mechanism 3, and draws, via an oil suction port 62q, an oil held in an oil reservoir 25 to supply it to the compression mechanism 2. The heat insulating structure 30A is disposed between the
oil pump 6 and the expansion mechanism 3, and limits a flow of the oil between an upper tank 25a, in which the oil suction port 62q is located, and a lower tank 25b, in which the expansion mechanism 3 is located, so as to suppress
heat transfer from the oil filling the upper tank 25a to the oil filling the lower tank 25b.