PURPOSE: To form a pattern simply ith high accuracy and excellent reproducibility by a method wherein laser beams are irradiated on part of the surface of an extruded shape and the portion irradiated by laser beams is etched to a desired depth to form a pattern.

CONSTITUTION: This method is to irradiate laser beams on a part of the surface of an extruded shape and to etch the laser beam irradiated portion by a desired depth. Accordingly, the laser beam irradiated portion becomes concave while the laser beam unirradiated portion becomes convex to make a solid pattern. In this way, it is possible to form any solid pattern as desired to improve the additional value of the extruded shape.