PURPOSE: To prevent unexpected economic loss at burglary, by destroying the function of a telephone set with an encryption code.

CONSTITUTION: When a call comes from other telephone set to a portable telephone set, a telephone number received via an antenna 1, a receiving circuit 2 is recognized at a control section 3 and a line is set between the telephone sets. When an encryption code specific to the portable telephone set is received and discriminated at the control section 3, the control section 3 transmits the control signal to a power supply 4 to close a switch S. Thus, an overcurrent flows to a fuse F, and it is blown, then each circuit in the telephone set can not function because of power interruption.