To provide a saw blade, forming a skin layer on the cut surface simultaneously with cutting, in the case of cutting foamed resin forming material used in a top plate of a drainboard.

The thickness T1 of a knife edge 2 of a saw blade 1 is smaller than that T2 of a metallic support part 4, and the saw blade is gradually increased in thickness from the knife edge 2 to the metallic support part 4 to be tapered.