The blower comprises: a blower case; a motor case; and a shaft pierced through the both cases. A first communication hole, which is formed in one of axial end faces of the motor case, introduces a part of compressed air into the motor case. A second communication hole, which is formed in the other axial end face of the motor case, discharges the compressed air to outside of the motor case. An external guidance path introduces the discharged air toward an outside face of the motor case. By actuating a motor, the compressed air, which has been introduced from the blower case into the motor case via the first communication hole, is discharged from the second communication hole, and the discharged air is introduced by the external guidance path and blown out toward the outside face of the motor case.