PURPOSE: To allow the correct comprehension of the temporal variation of temperature by sustaining the condition indicating a specific temperature when the specific temperature is exceeded.

CONSTITUTION: The temperature indicator comprises a bimetal 6 contained in a case 2, a pointer 8 operable depending on the elongation/contraction of the bimetal 6, a hook 9 disposed at the tip of the pointer 8, and a part 10 to be engaged with the hook 9 disposed at a predetermined graduation on a dial 3 identifiable from the outside of the case 2, wherein the hook 9 is engaged with the engaging part 10 when the pointer 8 points at a specific temperature and secured in place nonreversibly.