A motor includes a stator having a winding wire wound thereon, a rotor, and a shaft. The motor is housed in a motor case, where the motor case has a cylinder part and a bottom part. A first terminal is disposed on the motor case, and has one end coupled to an end of the winding wire, such that the wire passes through a first opening on the bottom part. A controller case is disposed detachably on the bottom part. The controller case has a controller housed therein, and has a second terminal that has one end electrically coupled to a power module and the other end engages with the first terminal to electrically couple the motor and the controller. A terminal holder is attached on the motor case to hold and support the first terminal.