Our development concerns an optical instrument-making, particularly the reflectometers - the instruments intended for a measurement of a reflection coefficient of the smooth surfaces by an extra accuracy method using an interflection of the controllable sample. At the same time a problem of measurement of the light-transmission factor for transparent samples (with or without any optical antireflecting coating) is solved including a possibility of the multiple passing of the radiation through the investigated sample. The purpose of this research was a creation of a metrological test bench to measure reflection coefficients of mirrors with the high-reflective (close to 1) multi-layer interference surfaces with the help of the high-precision, noninvasive and nondestructive method and the measurement of the light-transmission factor for transparent samples. The detailed calculation of the optical scheme for several wave bands has been made. An analysis of the influence of different factors on a measurement error has been carried out. It has been demonstrated that the use of the offered reflectometer would allow to reduce the measurement errors.