A medium accommodating device includes: a loading unit on which media are loadable in an up-down direction; a first restricting unit that is provided in the loading unit and restricts a position of a side portion of a medium in a width direction intersecting a transport direction of the medium according to a dimension of the medium in the width direction; an air supply unit that supplies air to plural media loaded on the loading unit to float and separate the plural media; a transporting unit that sequentially sends the media that are floated and separated by the air supply unit; a photographing unit that photographs a state in which the media are floated and separated by the air supply unit from an outside of the medium in the width direction; a second restricting unit that is attached to the loading unit when a narrow medium having dimensions in the width direction smaller than dimensions of the medium is loaded on the loading unit, and restricts a position of a side portion of the narrow medium in the width direction; and a focal distance changing unit that is installed at a position facing the photographing unit in a state in which the second restricting unit is attached, and aligns a focal point of the photographing unit with the side portion of the narrow medium in the width direction by changing a focal distance.