A contactless power transmitting device is provided including a power transmitting device functioning as a charger, a power transmitting-receiving sharing device functioning as a charger and including a secondary battery, and a power receiving device including a secondary battery. The power transmitting-receiving sharing device is used as a power supply for portable computers. The power receiving device is used as a power supply for cellular phones. The power transmitting device forms a contactless power transmitting device respectively by electromagnetically coupling to either the power transmitting-receiving sharing device or the power receiving device to charge the secondary battery or the secondary battery. The power transmitting-receiving sharing device forms the contactless power transmitting device by electromagnetically coupling to the power receiving device. In this case, the power transmitting-receiving sharing device charges the secondary battery included in the power receiving device.