A temperature detection device and method that can simply and accurately detect the presence or absence of abnormal heating of a conveyor belt. Correlation data between an electrical resistance value of a passive IC tag embedded in a conveyor belt and a temperature of the IC tag when it is activated is grasped in advance when the tag receives a transmitted radio wave from a non-contact detector. Data of electrical resistance value when the IC tag is activated is received by the detector through a returned radio wave returned from the tag in response to the transmitted radio wave transmitted from the detector toward the tag embedded in the conveyor belt running. A temperature at a position of the conveyor belt where the tag is embedded is calculated in accordance with the data of the electrical resistance value received and the correlation data.