An original scanning apparatus is provided in which a translucent member can be easily cleaned. A glass (31) on a reading surface is configured openable and closable with respect to an upper original conveying guide (24), whereby a surface (C) on the inner side of the glass (31) in a reading window can be easily cleaned and deterioration of an image due to a dust inside the apparatus adhering to the surface (C) on the inner side of the glass (31) can be prevented.