A wireless AV system includes a central wireless unit, serving as a base device, and a TV main unit. The TV main unit includes an SS transmitter/receiver (T/R) unit, a TV section, a TV microcomputer, and a second SS-CPU. The SS T/R unit receives an MPEG-2 stream and command transmission data both of which are transmitted from an SS T/R unit of the central wireless unit, and decodes the MPEG-2 stream and the command transmission data so received. The TV section displays a video signal and outputs an audio signal. The TV microcomputer controls the TV main unit entirely. The second SS-CPU detects a communication condition between the central wireless unit and the TV main unit according to a received radio wave field intensity and a retransmission request made based on an error rate. The TV microcomputer causes the TV section to OSD-display such reception sensitivity information messages that video and/or audio data has been interrupted, that transmission channels are being switched, that connection are being made, and that the TV main unit is out of communication range, according to the. communication condition so detected. Thus, a user is free from a feeling of discomfort even when a display image is interrupted due to transmission channel switching etc. Thus, user-friendliness can be improved.