This paper presents an experimental analysis on manufacturing and geometrical characterization of micro-channels fabricated on AISI 316L steel by laser milling. Micro-channels, with rectangular section, were fabricated keeping the process parameters and the number of removed layers constant and varying the width of each channel. The geometry of micro-channels was revealed using a 3D digitizing system Optimet Conoscan 4000, which combines a non-contact, single-point measuring sensor based on conoscopic holography technology with x-y positioning with a resolution equal to 15 microns on the x and y axes. The use of this measurement technology allowed obtaining complete information of the shape geometry and dimensions of built channels.