When a sound presence/absence detector (12) detects a sound absence interval, a non-modulated carrier signal is outputted in an area used to transmit speech data that are included in transmission data having a frame structure and that correspond to the sound absence interval. That is, an FSK modulator (14) causes a transmitting circuit (15) to output the non-modulated carrier signal from a wireless communication apparatus (100) in the area used to transmit the speech data corresponding to the sound absence interval. In the meantime, a four-level FSK modulated wave signal is outputted in the areas other than the one of the sound absence interval. A non-modulation discriminating data for allowing the sound absence interval to be determined are included in an area of channel identifying information included in the transmission data having the frame structure, and allow a communication terminal apparatus at the receiving end to avoid any unstable operations. The present invention is suitable for narrowed bands of communication paths and reduces the affections on adjacent channels.