Abstract: A proposed diamond cutter is provided with man-made diamond grains on the circumference of a disc base plate, and is formed with slits from the outer circumference to the central part thereof. The slit is angled about 30.degree. with respect to a radial direction of said plate, so that the heat caused during cutting is prevented from running toward the central part, thereby to save the base plate from crackings. Minor cutting edges are also provided in addition to said angled cutting edge, and the cutting effect is increased.