To provide a paper sheet accommodating device capable of setting a sheet stacking plate easily.

The sheet accommodating device is structured so that the part around a rotational fulcrum 24 of a bottom 28 will not overlap on a locking rib 20, viewed in the horizontal direction, when the bottom 28 is rotated to outside the rotation range in the normal operation. Accordingly when the bottom 28 is to be set on a base cassette 25, the rotational fulcrum 24 of the bottom 28 and the locking rib 20 do not contact even if the rotational fulcrum 24 is deflected inward, and it is possible to set the bottom 28 easily on the base cassette 25.