本发明之课题在于提供一种同时满足稳定之形状精度与加工性，而且可抑制斜切割的切割刃。本发明之平刃状切割刃1之系切割运行部的刃尖部7系具有：左刃面9a、右刃面9b，系从基部5之左右双面倾斜成彼此接近；；及刃尖尖端11，系以连接左刃面9a与右刃面9b之方式所形成，并具有凸弯曲面；沿着左刃面9a与右刃面9b之2条直线13a、13b的交点与刃尖尖端11的最短距离系1μm以上且10μm以下，而且，刃尖尖端11的长度相对中心线21在左右相异，其差异系1μm以上且20μm以下，进而，沿着该左右刃面之2条直线之交叉角度的内角系4度以上且60度以下。

An object of the invention is to provide a cutting blade which satisfies both stable shape accuracy and workability and which is capable of preventing oblique cutting. A cutting blade 1 of a flat-blade type according to the present invention has a base portion 5 and a blade edge portion 7 as a cutting executing part. The blade edge portion 7 has left and right blade faces 9a and 9b inclined from left and right surfaces of the base portion 5 towards each other, and a blade tip 11 having a convex curved surface connecting the left and the right blade faces 9a and 9b. A shortest distance between the blade tip 11 and an intersection point of two straight lines 13a and 13b extending along the left and the right blade faces 9a and 9b is not smaller than 1 &mgr; m and is not greater than 10 &mgr; m. The blade tip 11 has different lengths on left and right sides with respect to a center line 21. The difference between the lengths is not smaller than 1 &mgr; m and is not greater than 20 &mgr; m, and an inner angle formed by two lines along the left and right blade faces 9a and 9b is not smaller than 4 degrees and is not greater than 60 degrees.