A motor-driven compressor is formed integrally with a compressor device for compressing refrigerant and a motor for driving the compressor device. The motor-driven compressor includes a drive circuit and a plurality of cooling fins. The drive circuit controls the operation of the motor. The drive circuit is provided on an outer surface of a wall of a refrigerant suction route. The plurality of cooling fins are formed on an inner surface of the wall of the refrigerant suction route. In such motor-driven compressors, the drive circuit may be sufficiently cooled without using cooling devices. As a result, providing cooling devices with the drive circuit in motor-driven compressors is no longer necessary.