A control unit controls a first DC motor and a second DC motor by detecting a rotational position thereof and includes first control means and second control means. The first control means performs a detection of the origin position pattern by controlling each DC motor to rotate toward one side within a detectable range. In case where the rotational position reaches one end of the detectable range, the second control means performs a detection of the origin position pattern by controlling the DC motor to rotate oppositely from the one side when the other DC motor is stopping, and performs a detection of the origin position pattern by controlling the DC motor to rotate oppositely from the one side after the rotational position of the other DC motor reaches the one end of the detectable range when the other DC motor is rotating.