A motor-driven compressor (10, 10A) comprising: a compression unit adapted to compress refrigerant; an electric motor adapted to drive the compression unit; a housing (11, 11A) that accommodates the compression unit and the electric motor; a cover coupled to the housing (11, 11A); a motor driving circuit arranged between the housing (11, 11A) and the cover and adapted to drive the electric motor; a metal terminal that electrically connects the electric motor to the motor driving circuit; and a coupling base coupled to the housing (11, 11A), wherein the motor driving circuit is coupled to the coupling base, the motor-driven compressor (10, 10A) wherein a refrigerant passage in which the refrigerant flows is arranged in the coupling base, each of the coupling base and the housing (11, 11A) includes an insertion portion (12b, 40h, 52b) through which the metal terminal is inserted in an inserting direction, at least one of the coupling base and the housing (11, 11A) includes a protrusion (42, 62, 65) that extends in a direction parallel to the inserting direction, wherein the protrusion (42, 62, 65) is separated from the insertion portions (12b, 40h, 52b) by a predetermined distance, at least the other of the coupling base and the housing (11, 11A) includes a receiving portion (12h, 52h, 61, 66) that receives the protrusion (42, 62, 65), and the coupling base is positioned relative to the housing (11, 11A) by connection of the insertion portion of the coupling base and the insertion portion (12b, 52b) of the housing (11, 11A) and by engagement of the protrusion (42, 62, 65) and receiving portion (12h, 52h, 61, 66), characterized in that the protrusion (42, 62) is a tubular portion (42, 62) that is arranged in one of the coupling base and the housing (11, 11A) and forms a communication passage (42a, 62a, 69), the communication passage (42a, 62a, 69) communicates the refrigerant passage and an interior of the housing (11, 11A), and the receiving portion (12h, 52h, 61) is a receiving hole (12h, 52h, 61) that is arranged in the other one of the coupling base and the housing (11, 11A) to receive the tubular portion (42, 62). a compression unit adapted to compress refrigerant; an electric motor adapted to drive the compression unit; a housing (11, 11A) that accommodates the compression unit and the electric motor; a cover coupled to the housing (11, 11A); a motor driving circuit arranged between the housing (11, 11A) and the cover and adapted to drive the electric motor; a metal terminal that electrically connects the electric motor to the motor driving circuit; and a coupling base coupled to the housing (11, 11A), wherein the motor driving circuit is coupled to the coupling base, the motor-driven compressor (10, 10A) wherein a refrigerant passage in which the refrigerant flows is arranged in the coupling base, each of the coupling base and the housing (11, 11A) includes an insertion portion (12b, 40h, 52b) through which the metal terminal is inserted in an inserting direction, at least one of the coupling base and the housing (11, 11A) includes a protrusion (42, 62, 65) that extends in a direction parallel to the inserting direction, wherein the protrusion (42, 62, 65) is separated from the insertion portions (12b, 40h, 52b) by a predetermined distance, at least the other of the coupling base and the housing (11, 11A) includes a receiving portion (12h, 52h, 61, 66) that receives the protrusion (42, 62, 65), and the coupling base is positioned relative to the housing (11, 11A) by connection of the insertion portion of the coupling base and the insertion portion (12b, 52b) of the housing (11, 11A) and by engagement of the protrusion (42, 62, 65) and receiving portion (12h, 52h, 61, 66), characterized in that the protrusion (42, 62) is a tubular portion (42, 62) that is arranged in one of the coupling base and the housing (11, 11A) and forms a communication passage (42a, 62a, 69), the communication passage (42a, 62a, 69) communicates the refrigerant passage and an interior of the housing (11, 11A), and the receiving portion (12h, 52h, 61) is a receiving hole (12h, 52h, 61) that is arranged in the other one of the coupling base and the housing (11, 11A) to receive the tubular portion (42, 62).