A housing is fixed to a vehicle. A shaft is rotatably mounted on the housing about a predetermined axis. A brake pedal is fixed to the shaft and operates around an axis of the shaft. A sensor device outputs a signal that detects a position of the shaft and the brake pedal relative to the housing, or a signal that detects a load applied to the brake pedal. A first fixing portion fixes a sensor component constituting at least a part of the sensor device to the housing or the brake pedal. A second fixing portion fixes the sensor component to the housing or the brake pedal using a fixing method different from that of the first fixing portion.