To correctly cut a sheet always in desired dimensions easily and rapidly without needing skill.

A sheet roll S1 wound with a plastic sheet is rotatably journalled to support plate parts 2a, 2b of a support frame 2, and feed rollers 7 coaxial with a shaft to be the rotational center of an operating lever 15 are rotatably journalled to the support plate parts below the sheet roll S1, and a keep roller 9 is provided to press the plastic sheet to the feed rollers 7. A ratchet 18 coaxial with the shaft of the operating lever 15 is engaged with a reverse rotation preventing click. This reverse rotation preventing click transmits only rotational force at the time of operating the operating lever 15 to the ratchet 18, and the operating lever 15 is regulated in its turning angle by an angle adjusting plate 16 rotatably fitted to the support plate part. A hot wire 29 is stretched below the feed rollers 7 and in the same direction as the axial direction of the feed rollers 7. When the operating lever 15 rotates the plastic sheet in a state of being held between the feed rollers 7 and the keep roller 9, by a turning angle set by the angle adjusting plate, the feed rollers 7 automatically pull out the plastic sheet below the hot wire 29 by the specified cut dimension.