Abstract: An interior cooling air flow is moved by an interior fan through an inside ventilation passage provided on an inside surface of a stator frame of a totally-enclosed type motor. An exterior cooling air produced by an exterior fan is passed through an outside surface of ventilation passage provided on an outside the stator frame. An inner heat radiation rib is provided in the axial direction on an inner face the inside ventilation passage so that the temperature rise of the motor can be reduced by an improvement in the cooling characteristic. In this way, a compact size totally-enclosed type motor having an improved cooling characteristic is obtained.