In the ADF of this invention, not only the conveying unit but also at least one of the paper feeding unit and the paper discharging unit are supported by a support frame via floating support mechanisms. The conveying unit and either one of the paper feeding unit and the paper discharging unit are provided with a plurality of contact pieces that come in contact with the platen glass and with the housing at the closed position of the support frame or the ADF. The load of either the paper feeding unit or the paper discharging unit is supported by said contact pieces at the closed position of the ADF.
