A control device to be used in a power receiving device that receives power from a power transmitting device by contactless power transmission includes a power supply portion that supplies power to a load based on power received by a power receiving portion, a communication portion that performs communication in which communication data is transmitted to the power transmitting device, and a control portion that controls the power supply portion and the communication portion. The control portion causes the communication portion to start the communication when an output voltage of the power receiving portion becomes higher than a first voltage, and causes the power supply portion to start power supply to the load when, after the communication is started, the output voltage of the power receiving portion becomes higher than a second voltage that is different from the first voltage.