PURPOSE: To provide a response device capable of reading information with the aid of an external device, which is in effect when information transmission is not possible via communications, and construct a moving body identifying device in which this type of response device is incorporated.

CONSTITUTION: A CPU 16 and RAM 18 of a response device 10 are connected electrically via a data bus with a breaker device 19 interposed. At the data bus tying the RAM 18 with the breaker device 19, another data bus is branched and is connected with a connector 20. The breaker device 19 a mechanical switch, and under normal operation, it does not obstruct the transfer of information between the CPU 16 and RAM 18. However, if any cause brings about incapability of operation of the CPU 16 or transfer means etc., the breaker device 19 is actuated to shut the data bus tying the CPU 16 to the RAM 18, and the connector 20 is connected with the mating connector on the cable leading to an external device which can read the information stored in the RAM 18. This enables direct access to solely the RAM 18 from the external device, and the information can be read.