PURPOSE: To measure the temperature of a nonmetal substance, for example, in a radiation field accurately by adhering a plurality of materials with different thermal coefficients of expansion in a macromolecular compound with physical properties that are equivalent to the energy absorption and specific heat of an object to be measured.

CONSTITUTION: In a temperature sensor, a macromolecular compound (for example, high-density polyethylene plate and methymethacrylate plate) where a thermal coefficient of expansion differs and energy absorption and specific heat are approximated to those of an object to be measured is adhered by an adhesive. When the temperature sensor is subjected to temperature change, the sensor is deformed due to the difference in the thermal coefficient of expansion following the temperature change. The amount of deformation is recorded, thus measuring the temperature of a nonmetal substance in a radiation field and a radioactive ray field accurately as compared with a bimetal-type thermometer using a conventional metal sensor.