An image reading apparatus, which has reading means for reading images recorded on sheets and carries out predetermined processing for the images read using the reading means, comprising first extracting means for extracting a plurality of predetermined patterns from the images read using the reading means, second extracting means for extracting the combination information regarding the combination of the patterns from the images read using the reading means, and judging means for judging whether the combination of a plurality of the patterns extracted using the first extracting means coincides with the combination information extracted using the second extracting means or not, the predetermined processing being carried out on the basis of the result of the judgment made using the judging means.