of the cpu 31 are adapted to control the power supply of the power supply ic 20 and the start or stop of the ir temperature measurement device 10 respectively in fig2 the gpo1 pin of the cpu 31 is coupled to an enable en pin of the power supply ic 20 so that the power supply ic 20 can be enabled again as commanded by an instruction received from the cpu 31 via the en pin once an interrupt is removed in an unused state i e no temperature measurement power supply to the ir temperature measurement device 10 is cut so as to prolong the operating time of the battery in the cellular phone 30 moreover the gpo2 pin of the cpu 31 is coupled to the active pin of the ir temperature measurement device 10 for controlling the start or stop of the ir temperature measurement device 10 in an unused state of the ir temperature measurement device 10 the cpu 31 causes both the gpo1 and gpo2 pins to be in a high level at this time the power supply ic 20 in fig2 is disabled that is no power is supplied to the ir temperature measurement device 10 also the vdd pin of the ir temperature measurement device 10 in fig2 is 0v referring to fig3 there is shown a top view of the cellular phone 30 incorporating the ir temperature measurement device 10 thereinto as shown the cellular phone 30 has the same appearance as a typical one the cellular phone 30 comprises a phone body 32 including a display 33 for showing data or the like a keypad 34 a microphone 35 a speaker 36 and an antenna 37 the ir.