To reduce the resistance with a sheet without cutting the sheet in a deviated manner from a reentrant angle line due to undulation or ruggedness of the sheet.

In a sheet cutting tool, a wheel-shaped corner-pushing roller (a), rolling rollers (b), and a cutter 2 are fitted to a supporting plate 1, the corner-pushing roller (a) is diagonal to the plane to be formed by connecting the corner-pushing roller to the lower part of two or more rolling rollers (b), the lower part of the corner-pushing roller (a) is positioned on the perpendicular plane relative to the plane from the end part of the supporting plate 1 or on the outer side of the perpendicular plane, and a cutter is fitted so that the tip 2' of the cutter passes on the line on which the corner-pushing roller is advanced or in the vicinity thereof.