An index tab forming system sequentially forms index tabs to a plurality of sheets without replacing a blade die. The index tab forming system includes a rotary die cutter 5 on which a long blade die that can form an index tab at any position of the sheet in the conveyance direction is mounted. Furthermore, the index tab forming system includes a rotational speed calculation unit configured to calculate the rotational speed of a conveyance roller pair 37 based on the rotational position of a die cut roller 50, a sheet position detection signal provided by a sheet detection sensor 40, the number of times of sheet conveyance, and a shift distance between respective index tabs and a conveyance roller control unit configured to control the rotational speed of the conveyance roller pair 37 based on the calculated rotational speed.

A cutting device for cutting a continuous body of an electrode plate, the electrode plate including a current collector plate, a first active material layer, and a second active material layer, the cutting device including: a first process unit that causes a first cutting blade to form an incision in the first active material layer; and a second process unit that causes a second cutting blade to cut the continuous body.