TSS5X-3 infrared emissivity detector is at room temperature, can quickly and conveniently measure the emissivity of various materials. It is applicable to numeralization of small changes in surface treatment of various research institutions, production lines and materials, measurement of the emissivity of heat storage and heat disconnecting materials, research and measurement of the emissivity of iron and steel plants and semiconductor materials, etc. When the infrared emissivity detector measures their emissivity, two standard measuring equipment with fixed emissivity can be used, one with a black surface rate of 0.97. The other has a mirror speed of 0.06.