PURPOSE: To provide an electric motor, for vehicle-driving, whose constitution including a driving system and a cooling system is made small and lightweight.

CONSTITUTION: An inverter mounting chamber 9, an inverter cooling chamber 8, and induction motor 15 and a motor-driven pump for refrigerant are incorporated integrally. A refrigerant passing the inverter cooling chamber 8 absorbs heat transferred from an inverter 11 to a radiation fin 13 through a heat- dissipating metal plate 10. A refrigerant which passes through a spiral refrigerant route 17 dissipates heat to the atmosphere from a heat exchange face on the outer circumference of a casing 2 and from a heat radiation fin 21 on a heat exchange face 22 at the lower part so as to lower a temperature, it cools the induction motor 15, and it flows into the inverter cooling chamber 8. At the same time, heat generated by the induction motor 15 by an electrified drive operation is discharged to the atmosphere from the outer circumferential face of the casing 2. A strong wind due to the running operation of a vehicle hits the lower part of the casing 2, a heat dissipating operation from the radiation fin 21 on the heat exchange face 22 is promoted, and the heat exchange efficiency of an electric motor is increased.