To provide a manuscript reading apparatus capable of surely preventing an output of abnormal image data caused at dust and dirt existing at a read position.

A dirt detection means detects whether or not abnormal pixels due to dirt exist at the read position on the basis of a plurality of line data outputted from a manuscript reading means and when the dirt detection means detects the existing of the abnormal pixels, the manuscript reading apparatus informs a user about a prescribed message and inputs an instruction whether or not the manuscript discriminated to have the abnormal pixels is to be outputted.