In a communication terminal that is capable of carrying out communications based on a plurality of communication standards, for example, a cellular phone, information representing a reception carrier frequency of a wireless channel being received by a cellular-phone functional block is output from a CPU to a contactless-IC-card-reader/writer functional block. In the contactless-IC-card-reader/writer functional block, a controller controls a switching circuit to switch a transmission carrier frequency being used so that harmonic components of an electromagnetic wave radiated from a coil antenna will not work as an electromagnetic-interference wave that affects reception sensitivity of the cellular-phone functional block.