1. A recording medium type discriminating method for discriminating the type of a recording medium, comprising the steps of: creating, as image information indicating surface conditions of the recording medium, image information containing information for each of a plurality of pixels corresponding to a predetermined area of a recording medium surface; detecting a gloss level of the recording medium surface; obtaining, from the image information, a parameter regarding the surface conditions of the recording medium; and discriminating the type of the recording medium based on the gloss level and the parameter.