There is provided an device-identifying system including: a controlling device capable of communicating with external devices via a network and using a wireless communication method to transmit an device-identifying signal, for identifying one of the external devices capable of communicating by the wireless communication method, to the one of the external devices without relying on the network; and a controlled device capable of communicating with the controlling device via the network, when the controlled device receives the device-identifying signal from the controlling device, the controlled device transmitting, to the network via multicast or broadcast, a response indicating that the controlled device has received the device-identifying signal, wherein when the controlling device receives the response, the controlling device determines that the controlled device having transmitted the response is the device having received the device-identifying signal transmitted from the controlling device.