To exactly detect temperature by preventing the occurrence of dew condensation at a dustproof plate at the front end of an optical system.
This detector has a condenser element 14 which condenses the IR rays radiated from an object 3 to be measured, an IR receiving element 12 for receiving the IR rays condensed by this condenser element 14, a cylindrical probe 17 through which the IR rays heading from the object to be measured toward the condenser element 14 and a light shielding body 15 which shields the incidence of the IR rays from the outside of the condenser element 14 on the IR receiving element 13. The front end on the probe 17 side of the light shielding body 15 is provided with the dustproof plate 16 such that the IR receiving element 13 exists behind the focal position of the condenser element 14. As a result, the dew condensation at the dustproof plate 16 does not occur even if the body temperature is measured at the ear hole at a low room temperature and, therefore, a measurement error is prevented and the exact temperature detection is made possible.
IMAI HIROHISA
KANAZAWA YASUYUKI
MORIGUCHI YOSHINORI
