1. A form recognizing apparatus for recognizing whether or not an input form image including multiple pages corresponds to any of multiple registered forms, the apparatus comprising: registration means for registering a feature amount and weight information of each page for each of the registered forms; page similarity calculation means for calculating a page similarity value of each page of each of the registered forms by comparing a feature amount of each page of the input form image and the feature amount of a corresponding page of each of the registered forms registered by the registration means; form similarity calculating means for calculating a form similarity value between the input form image and each of the registered forms by weighting the page similarity values of each page calculated by the page similarity calculation means by using weight information of each page of each registered form registered by the registration means; and registered form determination means for determining a corresponding registered form corresponding to the input form image based on the form similarity values of each of the registered forms calculated by the form similarity calculating means.