Evaluation of the roughness profile of solid samples, indicating the average roughness (Ra) or other quantitative numerical parameters of interest. The equipment has a mechanical rod with a thin metal tip, which runs along a pre-determined profile of the sample surface at a constant speed. The vertical movements of the probe are used to evaluate the roughness profile of the samples. The technique is useful for evaluating the surface regularity of materials of different nature. In the case of ceramic tiles, it is related to slip resistance.