A sheet positioning member is provided on a sheet placing surface in such a way as to be movable in a predetermined first direction. The sheet positioning member includes a moving body, an abutting portion, an operation member, and a cam portion. The moving body moves in the first direction on the sheet placing surface. The abutting portion has an abutting surface that abuts on the side end portion when the sheet positioning member positions the sheet. The operation member is supported by the moving body so as to be pivotable around a support shaft that extends in the first direction, on a side of a back surface of the abutting portion. The cam portion displaces the abutting portion toward the side end portion by being pressed by the operation member in response to a pivoting operation of the operation member.