A communication apparatus includes a short-range communication unit and a long-range communication unit that communicates via electromagnetic waves in a range wider than a communication area of the short-range communication unit. The communication apparatus further includes a session key generating unit that generates a random number and uses the random number to generate a session key. In addition, the communication apparatus includes an encrypting unit that encrypts the session key. The communication apparatus uses an encryption key transmitted from an external communication apparatus to encrypt the session key into an encrypted session key, transmits the encrypted session key to the external communication apparatus, and receives from the external communication apparatus a communication switching request signal to request a switching from a short-range communication by the short-range communication unit to a long-range communication, with the session key, the long-range communication unit.