PURPOSE: To easily measure the body temp. of an examinee without imparting an unpleasant feeling or pain to the examinee, by providing a temp. sensor in the vicinity of the leading end of an ear plug-shaped housing so as not to be brought into contact with the skin.

CONSTITUTION: A temp. sensor 14 is provided to the leading end of an ear plug-shaped housing 10 so as not to be brought into contact with the external auditory miatus 12 at the time of mounting. This temp. sensor 14 detects the quantity of heat radiated from the surface of the external auditory miatus 12 becoming constant temp. to measure the temp of an earhole. The output of the temp. sensor 14 is amplified by an amplifier 16 and displayed on a display device 20 by a driver 18.