A medium placement device configured to have a medium discharged from a discharge unit of a processing device placed therein, and includes: a placement unit including a plurality of placement surfaces, with different angles with respect to a horizontal direction, that are disposed along a discharge direction of the medium, the placement unit being configured to have the medium discharged from the discharge unit placed thereon; and a plurality of restricting members disposed facing the placement unit along the discharge direction, the plurality of restricting members being configured to come into contact with the medium from above. In an initial state in which the medium is not placed, a distance in a gravitational direction between a first end of each of the plurality of restricting members on a placement unit side and one of the plurality of placement surfaces that faces the first end in the gravitational direction is constant.