There is provided a communication device capable of easily identifying a communication partner even when the communication device does not have a high processing ability and securely sharing a session key with the communication partner. The communication device includes a proximity active communication unit (101) for transmitting an enquiry signal via an electromagnetic wave to an approaching external communication device and waiting for a response to the enquiry signal; a wide-range communication unit (104) capable of performing communication via an electromagnetic wave in a range larger than the communication-enabled range of the proximity active communication means; a switching unit (111) for switching to one of the communication units: a proximity active communication unit and a wide-range communication unit; an asymmetric key generation unit (102) for generating a pair of an encryption key and a decryption key corresponding to the encryption key. The communication device uses the decryption key to decrypt the encrypted session key transmitted by the external communication device and transmits a communication switching request signal requesting the external communication device to switch to the wide-range communication unit for communication.