A control device is for a human-powered vehicle that includes a vehicle component and a plurality of detectors. The detectors are configured to detect information related to a vehicle speed of the human-powered vehicle in which the information related to the vehicle speed differs between the detectors. The detectors includes at least a first detector. The control device includes an electronic controller. The electronic controller is configured to control the vehicle component in accordance with an output of the first detector in a case where the output of the first detector is in a first state. The electronic controller is configured to control the vehicle component in accordance with an output of a predetermined detector that differs from the first detector among the detectors in a case where the output of the first detector is not in the first state.