A communication apparatus including a noise eliminator performing noise reduction processing to cancel a digitized signal received via a receiving antenna, a code decoder, connected to the last stage of the noise eliminator, that decodes the digitized signal that has been subjected to noise reduction processing, a desired-signal detector that limits the noise reduction processing by the noise eliminator when a digitized signal corresponding to a known form of modulation of a desired signal is received by the code decoder, a code interpreter, connected to the last stage of the code decoder, that interprets a decoded signal obtained from decoding by the code decoder, and a controller that disables limitation of the noise reduction processing when a decoded signal not corresponding to a known form of encoding of a desired signal is received by the code interpreter.