An electronic control unit includes a casing and a cover which are mutually bonded. A drive circuit board which drives a motor unit is fixed to the cover and, on the other hand, a control circuit board which controls the drive circuit board is fixed to the casing. An electrical connector which supplies an electric power to each board and a motor unit is attached on an opening section of the casing. First power supply terminals of this electrical connector and the motor unit and second power supply terminals of the drive circuit board are directly electrically connected by a bonding of both of casing and the cover.