The geometrical dimension laser meters patterned in accordance with triangulation scheme were used under development of the rolled product thickness meter and geometrical dimension monitoring device of the railway wheels. When used in such devices, the special feature of application of the laser meter lay in the inclinations of the monitoring object surface, when moving at designated range of angles plus or minus psi0. The quantitative evaluation of the measurement error geometrical component is necessary in evaluating the accuracy characteristics of the meter as a whole. For example, the measurement error of the rolled products thickness meter which has a linear field of vision may not exceed 12 mm (epsilon less than or equal to 20 micrometer). The measurement error of the railway wheels geometrical dimensions meter having the field of vision 2y approximately equal to 60 mm for each measurement channel may not exceed 300 micrometers (epsilon less than or equal to 300 micrometer).