To easily measure and evaluate the temperature of a part which can not be directly entered or observed by men and is even sealed.

One end of a coil-shaped bimetal 5 is fixed to a frame 1, and the other end is connected to a shaft 2 rotatably supported at the frame 1 to transmit the deformation of the bimetal 5 to the shaft 2 as rotation. The rotation of the shaft 2 is converted into displacements in the longitudinal direction of a pin 8 via a cam 7, and the pin 8 holds its maximum displacement. It is possible to measure and evaluate the highest temperature reached from the start of temperature measurement to its completion at a point of temperature measurement or its temperature history by the displacement finally held by the pin 8.