In a stacker for successively stacking cut papers on a bottom plate, a winding shaft for winding a non-cut continuous paper therearound is provided on a back side plate so as to project substantially perpendicularly to the paper restriction surface of the back side plate. This structure of the stacker makes it possible to stack the cut papers successively on the bottom plate and also makes it possible to easily wind the continuous paper around the winding shaft. In the stacker for successively stacking cut papers therein by inserting a cut paper beneath the previous stacked papers comprising a paper press for pressing the stacked papers from the top surface thereof and a press force switching mechanism for contacting the paper press and applying press force to the stacked cut papers until the stack height of the stacked papers reaches a prescribed value and for releasing the application of the press force when the stack height of the stacked papers exceeds the prescribed value. This structure makes it possible to apply always an appropriate press force to the stacked papers and to stack the papers on the bottom plate with assurance.