A medium feeding device includes a device body, a tray that regulates and contains a plurality of kinds of media of different sizes in a loading area according to the sizes of the media, and a detection lever that detects whether or not the media are properly loaded in the tray. In a state in which the tray is contained in the device body, when the media are not properly loaded in the tray, the detection lever moves to a non-load detection position. When the media are properly loaded in the tray, the detection lever moves to a load detection position with a front end part being oriented toward the tray containing side, and when a pressing force is applied to the detection lever at the non-load detection position from the tray containing side, the detection lever retreats toward the tray pulling out side.