PURPOSE: To detect temperature rising and dropping continuously by forming this device out of at least one supporting structural body and at least one conductor fixed onto the supporting structural body.

CONSTITUTION: This device is provided with the first supporting structural body 110 serving as a main member, an optional supporting structural body 130 and a conductor 120. The conductor 120 is fixed onto the structural body 110 and connected to a mesh. The conductor 120 fixed between the structural body 110 and 130 is composed of various conductive mediums. The conductor 120 expands or shrinks with its own conductivity retained as a result of the structural bodies 110, 130 expanding or shrinking with heat increase or decrease. When the conductor 120 is expanded or shrunk, the resistance/conductivity associated with the conductor 120 changes. The change in resistance/conductivity is monitored immediately by an electron monitoring instrument, for example, an electric circuit, which is calibrated exactly so as to monitor temperature associated with thermal expansion of the structural bodies 110, 130 precisely.