A transceiver of a radiation detecting cassette sends cassette ID information stored in a cassette ID memory to a transceiver of a console via a transceiver of an image capturing apparatus by way of wireless communications. An ID determining unit determines whether cassette ID information which matches the cassette ID information received by the transceiver is stored in a cassette ID memory or not. If the ID determining unit judges that both cassette ID information match each other, the transceiver sends the cassette ID information and an activation instruction signal to the transceiver by way of wireless communications.