To provide an adhesive tape cutter and a tape cutting method superior in easiness-to-use while easily and beautifully cutting various adhesive tapes by relatively small force.

The adhesive tape cutter and the tape cutting method thereby include a holder 3 of a cylindrical body capable of attaching-detaching a core of an adhesive tape winding body, a cutter 5a of carving a blade of a small pitch angle shape over the short size side from the long size side on a circular arc on the plate-like base lower end having a width of a tape width or more, a pressurizing piece 4 arranged in a blade upper part and a rotary shaft part 6a arranged in the vicinity of the blade; and can cut the tape by moving a tape position abutting on the blade of the cutter to the short size side from the long size side by downward pressurization to the pressurizing piece and rotation with the axis of the rotary shaft part as a fulcrum.