MEDIUM STORAGE DEVICE

A medium storage device comprises a housing, a platform, a door, and a platform movement limiting portion. An accumulation space for accumulating paper-shaped medium is formed inside the housing and communicates with the external space through an opening portion. Medium is accumulated on an accumulating surface side of the platform inside the accumulating space. The platform moves to the accumulating surface side or a reverse side in the accumulating space. The door is installed on the housing through a preset rotation supporting portion and is rotatable. When the door is opened, the opening portion is opened, and visits from the outside to the accumulating space are allowed. When the door is shut, the accumulating space is shielded from the outside. A rod is arranged on the side of the opening portion opposite to the rotation supporting portion. The platform movement limiting portion is switched between an unlocked state and a locked state. In the unlocked state, the movement of the platform is permitted whe