A motor assembly includes a motor, a circuit board on which a control circuit to control the motor and a plug unit are mounted, and a supporting member which supports the motor and the circuit board. The motor is provided with a socket unit in which the plug unit is fitted. The supporting member has a board supporting portion to support the circuit board, a motor supporting portion to support the motor, and a supporting member engagement portion. The plug unit has a plug unit engagement portion which is engaged with the supporting member engagement portion. The plug unit engagement portion is engaged with the supporting member engagement portion when the plug unit is fitted in the socket unit.