The communication apparatus intermittently carries out receiving operation during a predetermined reception period. The apparatus includes a wireless communication section for carrying out wireless communication, which includes a carrier sensor for sensing a carrier at the beginning of the communication, and a carrier sense switching section for using carrier sense levels different between packet transmission and reception to switch the carrier sense level of the carrier sensor according to the packet. Thus, the apparatus can use and flexibly adjust the optimum carrier sense level for the intermittent receiving operation within the reception period.