To solve the problem that a temperature sensor using a thermoelectric element requires an electrical interconnection during measurement, that the measurement of a temperature is difficult at a rotating body or in an environment of high airtightness and that an error by a measuring operator is large because a paint sensor judges a change in a color by a human.

The temperature sensor and the temperature measuring method which do not require the electrical interconnection and whose error is small are provided. In the creep deformation temperature sensor, a casing is screwed to one end of a creep deformation body which is composed of a metal material having a known creep deformation curve and in which screw threads are formed on both ends, a nut is screwed to the other end of the creep deformation body so as to come into contact with the end part of the casing, the nut is tightened, and a tensile force is given to the creep deformation body. The sensor is exposed for a definite time in a high-temperature environment, it is taken out, a relaxation amount which is calculated by measuring the residual stress of the creep deformation body is compared with a known creep deformation curve, and an exposure temperature is found.