An electrostatic copying apparatus in which the paper is fed from a cassette. The cassette has a casing for a stack of sheet-like copying papers of at least two different sizes, said casing being a box-like housing having an open top, a closure plate mounted detachably on the top surface of the housing and having at least one display window, and at least two restricting members mounted in spaced-apart relation in the longitudinal direction of the cassette casing so that they can pivot about the axial line of the cassette casing extending in the transverse direction of the cassette casing, each of the restricting members having a restricting portion for restricting the rear end of copying papers to be accommodated in the housing and a display portion having an indication of the size of copying papers, the display portion being positioned adjacent to the display window when the restricting portion is brought to its operative position beneath the closure plate.