To provide equipment having a function for detecting a fire at the most familiar place even in any state by using a portable telephone set, and for preventing the loss of life of a portable telephone carrier by issuing warning simultaneously with the detection of an abnormal situation.

A portable telephone set includes: a convection air hole configured of a convection air inlet thin pipe 4 and a convection air outlet thin pipe 6 in a portable telephone body 1 or a display 3; a space box 5 equipped with a light emission diode 7 and an optical sensor 8 at the intermediate section; and a smoke detection mechanism for, when smoke generated in a fire passes through the space box 5, detecting scattered rays of light generated due to smoke from the rays of light of the light emission diode 7 by the optical sensor 8. Thus, it is possible to inform a portable telephone set carrier under sleep of the generation of an emergency situation to awake the carrier by generating the incoming voice of the portable telephone set simultaneously with the detection of smoke.