MARK DETECTION DEVICE

PROBLEM TO BE SOLVED: To make marks on a document such as a mark sheet detectable with high accuracy at reduced cost.SOLUTION: A multifunction machine 1 comprises a document reading unit 5 and a conversion unit 102 which, by OCR-processing each part of an image shown by the read data from the document reading unit 5, checks to see which one of a plurality of standard patterns it matches, and converts it to a character correlated to the standard pattern which was found matching. A client computer 7 includes a determination unit 74 which, when the converted character from the conversion unit 102 is a first standard character, determines that the image part on the document or the subject of determination is a mark, and which, when not the first standard character, determines that the image part or the subject of determination is not a mark.