To provide a heat exchanger integral type horizontal compressor with built-in accumulator in which a function of accumulator is added and a heat exchanger is integrally provided.

This compressor has a double structure in which an inside closed vessel 1 is provided within a horizontal outside closed vessel 16. In the inside closed vessel 1, an electric motor part 2 and a rotary compression part 3 comprised of a first-stage rotary compression part 3a and a second-stage rotary compression part 3b driven by the electric motor part 2 are provided. An intake pipe 13 is arranged to an upper part of a space S between the outside closed vessel 16 and the inside closed vessel 1, and is connected to the first-stage rotary compression part 3a, and an oil reservoir 19A including a liquefied refrigerant is arranged to a bottom of the outside closed vessel 16. A small-sized intake pipe 13a and an delivery pipe 14 for delivering a coolant gas to an outside are arranged to the second-stage rotary compression part 3b. A return pipe 18 is connected to a side end part of the outside closed vessel 16, and the heat exchanger 21 is arranged to the upper part of the space S. An end of the return pipe 18 is connected to an outlet of an evaporator, an end of the delivery pipe 14 is connected to an inlet of a gas cooler, an inlet of the heat exchanger 21 is connected to an outlet of the gas cooler, and an outlet of the heat exchanger 21 is connected to an expansion valve.