To prevent occurrence of chattering and a stain on a document when double feeding occurs.

In a document carrying part (an automatic sheet material feeder) having a separating flapper 50 for perspiration, a separating belt 12 for main separation, etc., when a plurality of documents are fed, the separating belt 12 returns only the uppers die document in the right direction shown in Fig. Where, the upper surface of the document is rubbed with the separating flapper 50. Meanwhile, many groove parts having average surface roughness (Ra) in the range of 0.1-500μm and a pitch of about 350μm or less are formed on the surface of the flapper 50. Thus, occurrence of chattering is reduced. In addition, the groove parts are continuously formed along the sheet feeding direction. Thus, the residence of an image material is prevented to prevent the following document to be fed from being stained.