A wireless communication apparatus in a first wireless communication system is equipped with a power detector for detecting power of a reception signal; an envelope detector for detecting an envelope signal of the reception signal; a signal determiner for determining whether the reception signal is a first signal to be used for a communication in the first wireless communication system, on the basis of a variation amount of the envelope signal; a wireless communicator for performing a wireless communication; and a wireless communication activator for activating the wireless communicator when the wireless communication apparatus detects power of the reception signal and determines that the reception signal is the first signal.