Abstract: A diamond scriber is ground at an angle from a tip face toward a ridgeline. Because of this, chipping is less liable to occur, even during high-load scribing of sapphire substrates of 100 ?m or greater thickness, or of substrates that have been chemically polished; further, a cutting edge of the diamond scriber has superior resistance to wear out. Accordingly, there can be provided the diamond scriber suited to substrates that must be inscribed at a high load, such as sapphire substrates of 100 ?m thickness or more or sapphire substrates chemically polished.