Sensor device, and disaster prevention system and electronic equipment each having sensor device incorporated therein

The sensor device is capable of detecting the occurrence of a fire and the type of the fire. The sensor device includes a detection element (1) made of an organic semiconductor element or an inorganic semiconductor element which varies in characteristic value (e.g. resistance) in response to both gas produced in a flaming-type fire and a smouldering-type fire. The variation in resistance caused by gas produced in a flaming-type fire is different in polarity from the variation caused by gas produced in a smouldering-type fire. The resistance of the detection element (1) is extracted by a resistance extractor (11) and then fed to a resistance decrease discriminator (12) and a resistance increase discriminator (13), whereby a decrease or increase in resistance of the detection element (1) is discriminated. An information output circuit (14) outputs a predetermined signal (Y1, Y2, Y3) depending on the discrimination results provided by the discriminators (12, 13), to thereby indicate occurrence of a fire (signal Y1) and the type of the fire (signal Y2 or signal Y3).