PURPOSE: To provide a device for bending a belt-like blade material, by which a circular-arc shaped blade material curved in the width direction can automatically be bent with high accuracy bent in the thickness direction.

CONSTITUTION: The device is equipped with a blade material feed mechanism 15 giving a circular-arc shaped belt-like blade material 1 curved in the width direction a feed along with the circular arc of the blade material 1. It is equipped with a thickness direction bending mechanism 16 giving the blade material 1 a bend in the thickness direction, making a diameter line connecting the center point of a virtual circle including the circular arc of the blade material 1 and one point of the circular arc a fold line. The blade material feed mechanism 15 is equipped with press rollers 8 and a drive gear 9 engaging with a comb-teeth shaped part formed on the circular-arc shaped inner end edge side of the blade material 1.