Vehicle generated voltage control device

Provided is a vehicle generated voltage control device, in which even when a monitoring/detection circuit fails to operate, reliability during the failure period is enhanced with respect to controlling the excitation current flowing through the field winding. In the device, a plurality of monitoring/detection circuits each detect the output voltage of a vehicle generator or a terminal voltage of a battery connected to the vehicle generator. Based on the outputs of the monitoring/detection circuits, the output voltage of the vehicle generator or the terminal voltage of the battery connected to the vehicle generator is then controlled to a target voltage by flowing and cutting off the excitation current flowing through the field winding of the vehicle generator.