A medium feeding device includes a lower portion unit in which a feeding roller is provided, and an upper portion unit in which a separating roller is provided and which is connected to the lower portion unit so as to be openable and closable. The lower portion unit has a cover member which covers a holding portion of the feeding roller while exposing a portion of the feeding roller to the transport path, and the cover member is configured to be removable in a direction including a component directed toward an upstream side in the transport direction by being attachable to and detachable from the lower portion unit.