1. An information medium recognition device for recognizing an information medium inputted by performing an offline input operation, the information medium recognition device comprising: detection means for scanning the information medium in different scanning directions and for detecting stroke densities corresponding to each of the scanning directions; inference means for converting the stroke densities in each scanning direction into compressed fuzzy densities by performing a fuzzy inference process on the stroke densities corresponding to each scanning direction, which are detected by the detection means, wherein the number of fuzzy densities in each scanning direction is less than the number of the corresponding stroke densities and is equal to a number of fuzzy rules preliminarily established in the inference means for converting the stroke densities into the compressed fuzzy densities; and judgement means for judging from the compressed fuzzy densities corresponding to each of the scanning directions whether or not the information medium is genuine.