PURPOSE: To improve the cutting capacity of a saw by a method wherein chips are properly curled and consequently smoothly discharged and yet respective segments are made in the same form.

CONSTITUTION: In order to cut steel material or the like, a circular saw is rotated at a predetermined rotational frequency (cutting speed) and a predetermined feed (depth of cut) is given to the circular saw 1 or workpiece material in order to continuously perform quantitative cutting by means of one by one tooth of the segment 3. Because the second rake faces 8, which are inclined backward with a lead angle and are plane symmetrical in form, are formed on the rake face 4 of the segment 3, chips are produced in a bent form and accordingly discharged smoothly. Consequently, the cutting load is applied uniformly over the whole cutting teeth, resulting in increasing the durability of the saw.