To correctly set the media weight of a recording medium.

A medium discrimination device includes a first roller pair 11 for conveying a medium, a first driving unit 21 for rotating the first roller pair 11, a second roller pair 12 arranged on the downstream side of the first roller pair in the medium conveying direction, a second driving unit 22 for rotating the second roller pair 12, a distance measuring unit 23 which is arranged toward a medium conveying path between the first roller pair 11 and the second roller pair 12 to measure the distance to the medium, and a control unit 20. The control unit 20 deflects the medium to be conveyed by the first roller pair 11 and the second roller pair 12, and discriminates the kind of the medium from the current to be supplied to the first driving unit 21 when the distance to the medium measured by the distance measuring unit 23 reaches the predetermined value.