A side cutting edge of a tip 20 fixed to the outer circumference of a circular saw blade body 11 has a inflexion point K at a portion at which the tip projects laterally to the greatest distance. An outer-circumferential-side portion of the side cutting edge has a negative radial clearance angle of not less than −1° but less than 0° at the inflexion point, and an inner-circumferential-side portion of the side cutting edge has a positive radial clearance angle of greater than 0° but less than −1° at the inflexion point. By virtue of this configuration, a cut surface having a better surface roughness as compared to that obtained conventionally can be obtained in cutting of a soft material such as wood by use of a circular saw.