1. An image processing device comprising: a character recognition unit that recognizes character codes from character images in image data and also detects character recognition certainty, which is a degree of correctly recognizing character codes; a conversion unit that converts the character images to character code data according to the character codes; and a judgment unit that judges whether the character images should be converted to the character code data, wherein said judgment unit judges whether all character images contained in a specific character image group formed as an assembly of multiple adjoining character images should be prohibited from being converted into character code data depending on the character recognition certainty of said character images contained in the character image group.