This invention enhances the security strength of wireless communications in the ad-hoc mode. To this end, it is checked if the communication apparatus and a terminal of a communication partner can concurrently use different encryption keys in correspondence with a plurality of communication destinations. When at least one of the communication apparatus and the terminal of the communication partner cannot concurrently use different encryption keys in correspondence with the plurality of communication destinations, an encryption key uniquely set in the wireless network is set as an encryption key for a communication with the terminal of the communication partner.