A paper feeding device includes: a reference guide surface that contacts a lateral end portion of a sheet-shaped medium along a guide path for transporting the medium; a tapered guide surface that is inclined outward from the reference guide surface toward an upstream side of a transport direction and contacts the lateral end portion of the medium; a paper feeding roller that rotates to transport the medium in a direction parallel to the reference guide surface while the paper feeding roller contacts a surface of the medium; and a medium cassette that stores the medium. The medium cassette stores the medium so as to be inclined with respect to the reference guide surface so that a rear end of the lateral end portion of the stored medium at a side of the reference guide surface is positioned outside an imaginary extension surface of the reference guide surface.