Patent ID: 7617756

Claim:
An index cutter configured to form a thumb index on a sheet, comprising: a flat plate-shaped first base member; a flat plate-shaped second base member rotatably coupled to a first outer end portion of the first base member at a first outer end portion of the second base member via at least one coupling pin, the second base member also having a second outer end portion opposed to the first outer end portion of the second base member; an engaging protruding portion protruding from the first outer end portion of the first base member in a direction of a longitudinal axis of the first base member, the engaging protruding portion having a first blade portion at a tip end portion of the engaging protruding portion on a front surface side of the engaging protruding portion; and an engaging recessed portion recessed from the first outer end portion of the second base member in a direction of a longitudinal axis of the second base member, the engaging recessed portion having a second blade portion at a tip end portion of the engaging recessed portion on a back surface side of the engaging recessed portion, wherein, when the first base member is fixed and the second outer end portion of the second base member is pressed so that the back surface side of the engaging recessed portion rotatably approaches the front surface side of the engaging protruding portion, and the engaging protruding portion is received in the engaging recessed portion, a part of the sheet on the engaging protruding portion is cut by the first blade portion and the second blade portion.