Abstract: Each ECU in a system configuration based on a motorized seatbelt retractor having an ECU combined with a motor shortens the harness length along which many currents flow as much as possible. A main ECU and a subsidiary ECU each have functions corresponding to those are provided to a control unit for controlling a motor for a motorized seatbelt retractor. The main ECU determines output start conditions and transmits commands, and the subsidiary ECU autonomously performs detailed motor current control and the like.

Abstract: To securely hold occupants without interruption during breakage caused by collision using each ECU in a system configuration based on a motorized seatbelt retractor having an ECU combined with a motor in which harness length along which many currents flow is made short. A main ECU and a subsidiary ECU each have functions corresponding to those are provided to a control unit for controlling a motor for a motorized seatbelt retractor, the main ECU determines output start conditions and transmits commands, and the subsidiary ECU autonomously performs detailed motor current control and the like. To securely hold occupants without interruption during breakage caused by collision using each ECU.