A control device for a power receiving device that receives power supplied from a power transmitting device by contactless power transmission, including a charger that charges a battery based on the received power, a discharger that performs discharging operation of the battery and power supply operation in which power from the battery is supplied to a power supply target, and a controller that controls the discharger, and the controller stops the power supply operation when a magnetic detection signal from a magnetic detection element becomes active.