In the CATV communication system, each channel comprises a down control channel which employs a carrier wave (fd0) and accommodates a down delay control channel slot and down assignment control channel slots therein, a plurality of down communication channels which employ carrier waves (fd1 to fd4) different from that employed in the down control channel and accommodate down communication data channel slots therein, and a plurality of up channels which employ carrier waves (fu0 to fu3) and accommodate up delay control channel slots, up assignment control channel slots, and communication data channel slots therein.