The determination of the roughness of technical surfaces plays an important role in scientific and industrial applications. Traditionally, the ISO conform determination of the roughness of a technical surface has been calculated using contact stylus instruments. In contrast to this, it is presented two non-contact (optical) measurement devices, which are able to reconstruct 3D models of technical surfaces with a vertical resolution down to 20nm and allows measuring their roughness in this experimental study. All measured data that were obtained from a contact measurement instrument and two non-contact surface measuring systems have been evaluated by using SPSS 15 (Statistical Package for Social Science) statistically and two mathematical models giving the values of Ra and Rz parameters have been established. Precise measurement and evaluation processes of this book have been carried out "Nanotechnology Laboratory of the Department for Interchangeable Manufacturing and Industrial Metrology of Vienna University of Technology".