To provide an auxiliary appliance for lessening the force to be applied by the hand in the work for cutting a plate material of paper having a thickness, plastic, foamed styrol, etc., with a small knife.

This auxiliary appliance comprises two rollers 2 which have a central spacing 6 wider than the thickness of the plate 1 of the small knife and rotate freely in parallel with the handle, a supporting part 4 which fixes the central shaft 3 thereof and a fixing part 5 which fixes the handle of the small knife. The rollers are so formed as to exist below the middle body part of the handle of the small knife.