A motor-driven turbo compressor comprising: a housing in which an impeller chamber (17, 19) and a motor chamber are formed; an electric motor accommodated in the motor chamber; a rotating shaft provided in the housing and driven to rotate by the electric motor; a first impeller and a second impeller accommodated in the impeller chamber (17, 19) and provided on the rotating shaft such that large diameter portions of the first impeller and the second impeller face each other; a first suction port formed in the housing and configured to suck a refrigerant into the impeller chamber (17, 19); a first discharge chamber formed in the housing and into which the refrigerant supplied to the first impeller via the first suction port and compressed by rotation of the first impeller is discharged; a second suction port formed in the housing; and a second discharge chamber formed in the housing and into which the refrigerant supplied to the second impeller via the second suction port and compressed by rotation of the second impeller is discharged, wherein the first impeller, the second impeller, and the electric motor are arranged in the axial direction of the rotating shaft in this order, the first impeller and the second impeller are smaller in diameter than the inner diameter of the motor chamber, the second impeller is smaller in diameter than the first impeller, the first discharge chamber is located in the outer side of the first impeller with respect to the radial direction of the rotating shaft, and the second discharge chamber is located in the outer side of the second impeller with respect to the radial direction of the rotating shaft, characterized by an intermediate pressure port formed in the housing and through which the first discharge chamber communicates with the motor chamber, wherein the intermediate pressure port is located in the outer side of the second discharge chamber with respect to the radial direction of the rotating shaft, and the second suction port communicating with the motor chamber. a housing in which an impeller chamber (17, 19) and a motor chamber are formed; an electric motor accommodated in the motor chamber; a rotating shaft provided in the housing and driven to rotate by the electric motor; a first impeller and a second impeller accommodated in the impeller chamber (17, 19) and provided on the rotating shaft such that large diameter portions of the first impeller and the second impeller face each other; a first suction port formed in the housing and configured to suck a refrigerant into the impeller chamber (17, 19); a first discharge chamber formed in the housing and into which the refrigerant supplied to the first impeller via the first suction port and compressed by rotation of the first impeller is discharged; a second suction port formed in the housing; and a second discharge chamber formed in the housing and into which the refrigerant supplied to the second impeller via the second suction port and compressed by rotation of the second impeller is discharged, wherein the first impeller, the second impeller, and the electric motor are arranged in the axial direction of the rotating shaft in this order, the first impeller and the second impeller are smaller in diameter than the inner diameter of the motor chamber, the second impeller is smaller in diameter than the first impeller, the first discharge chamber is located in the outer side of the first impeller with respect to the radial direction of the rotating shaft, and the second discharge chamber is located in the outer side of the second impeller with respect to the radial direction of the rotating shaft, characterized by an intermediate pressure port formed in the housing and through which the first discharge chamber communicates with the motor chamber, wherein the intermediate pressure port is located in the outer side of the second discharge chamber with respect to the radial direction of the rotating shaft, and the second suction port communicating with the motor chamber.