The visualization technique using an infrared radiometer has been widely used to estimate a two-dimensional temperature distribution on a surface. We have previously proposed various characteristics of the radiative properties for nonmetal surfaces on which the gray-body approximation can be used. However, the gray-body approximation can not be applied to glossy metal surfaces, because the influence of the reflected energy on the temperature measurement becomes severe. A pseudo-gray-body approximation is therefore proposed to estimate a temperature field on metal surfaces and its applicability is confirmed using an infrared radiometer with three detection wavelength bands.