To regulate the cut position without wasting a film by setting the start timing at the position of origin of a horizontal seal member based on the feed of the film until the cut position of the film reaches the cut position from the time when a match mark is detected.

A film feed counter 11 is operated when a match mark sensor 1 detects a match mark m, and the feed of a film f from the match mark position is measured as the pulse number. When the film f passes the cut position B in one operation pattern, a belt drive motor 3 is stopped, and the pulse number corresponding to the feed of the film f up to this point is preset as the reference value to a film feed storage means 12. Then, the movement of horizontal seal jaws 4, 4 from the match mark detection point to the cut position B is calculated based on the reference pulse number inputted as the feed of the film f to calculate the start timing.