PURPOSE: To easily execute cutting work by weak force regardless of the thickness and hardness of an object to be cut by providing an auxiliary member to be abutted near the tip of a rotary blade or arranged close to the tip of the rotary blade and to be extended from an inner direction to an outer direction in the radial direction of the tip along the radial direction of the rotary blade.

CONSTITUTION: In a cutting part 4, a rotary blade 6 is provided to be rotated and driven by a motor M and in the side direction of the rotary blade 6, a fixed blade 7 is provided as the auxiliary member. The base end part of this fixed blade 7 is fixed to the inner surface of the cutting part 4 and the fixed blade 7 is abutted near a tip 53 of the rotary blade 6 or arranged close to the tip 53 and arranged over from the inner direction to the outer direction in the radial direction of the tip 53 along the radial direction of the rotary blade 6. Thus, paper can be cut without fail regardless of the thickness or hardness of the paper.