Equipment for measuring the temperature dependence of the reflectance of metal mirror surfaces is described. The multiple reflection method is used to increase the measurement accuracy. The main component of the equipment is a two-mirror multipath cuvette. One of the mirrors of the cuvette is a standard mirror, and the second can be heated to a temperature of 500 degree C in air or in an atmosphere of the light inert gases (He, Ne). The measurements were made simultaneously at wavelength of 0. 63 mu m and 10. 6 mu m. The error in measuring the reflectance is plus or minus 0. 002 at a wavelength of 0. 63 mu m, and plus or minus 0. 004 at a wavelength of 10. 6 mu m.