A motor control unit includes two circuit boards accommodated in a board housing, and a connection holder placed on an outer face of the board housing. The connection holder includes external connection terminals and connection pins. Each one of the circuit boards is provided with multiple through-holes for receiving the connection pins, each of which is formed of an external connection pin and an internal connection pin. The connection holder and the circuit boards are placed such that the connection pins penetrate the through-holes of the circuit boards respectively.