Abstract: The present invention relates to a process and a device for perforating a metallic piece of elongated shape and with straight generatrix, with a view to obtaining, in several successive passes, a pattern which extends over a considerable part of the length of said generatrix and which is constituted by a large number of adjacent perforations in the lateral wall of this piece, said process consisting in repeating at least one elementary pattern which comprises a part of said perforations and which extends over the whole height of the pattern to be made. According to the invention, this elementary pattern is made in one pass, two adjacent elementary patterns being made during different passes. The invention is more particularly applicable to the precision-production of technical and decorative perforations.