To provide a tab-forming tape cutter capable of forming a tab being a knob portion in which sticky surfaces are adhered in a fixed length at the tip of a sticky tape, and easily forming a tab even by a narrow sticky tape.

A tab-forming tape cutter is made up of a tape cutter body 10, a sticky tape 20, a tape installation portion 30, a tape-cutting portion 40, and a tab-forming portion 50. The tab-forming portion is made up of a fixed adhesion-holding portion 60, and a swinging portion 70 provided with the swinging adhesion-holding portion. The swinging portion, in order to form a tab by folding back the tape by the swinging adhesion-holding portion which moves forward in an approximately elliptical arc while maintaining adhesion of a sticky tape in drawing out the sticky tape and moves backward in an approximately elliptical arc while maintaining adhesion of a beginning portion of a remaining tape in cutting off the sticky tape, is configured of a swinging base portion in which the swinging adhesion-holding portion is provided at the top end and a long shaft hole is bored at the bottom end, a first shaft body, a swinging control piece, a second shaft body, and an elastic body.