To restrict the operation of particular functions of a portable radio terminal device and to start the operation of the particular functions by providing the portable radio terminal device with a means for remotely controlling its operation.

This portable radio terminal device is provided with an automatic connecting means for automatically connecting a call from a calling source by the coincidence of a fixed condition, and a DTMF (dial tone multi frequency) signal recognizing means for recognizing a number corresponding to a personal identification number and a prescribed operation by a DTMF signal inputted from the calling source.