To provide an MICR reading mechanism with a general scanner having a center paper feeding mechanism for accurately reading MICR characters even when documents different in paper size are mixed and stacked.

A sensor detects the ends in the main scanning direction of the documents stacked on a hopper. When it detects the ends in the main scanning direction of the documents, an MICR reading head is moved from the position as a criterion to a position where the predetermined MICR characters are printed. At this time, the paper not to be skewed abuts on a paper feed roller to correct skewing with over-feed control.