The present invention provides a manufacturing method for accurate, fine and efficient processing of a work piece to be processed and prevention of graphitization of the work piece to be processed, when sintered diamond is processed by a laser beam.The method provides process comprising steps of (a) irradiating outer circumference of a scribing wheel 2 with a laser beam from the side of the wheel, (b) moving the laser beam relative to the wheel 2, (c) forming continuously along the circumferential direction in the required space fine grooves with openings directed radially on a ridge site, (d) irradiating the laser beam onto the site to be processed at a speed of the laser beam relative to the work piece, and (e) forming the work piece into a minute shape within a depth of less than 200 μm.