1. A function extraction apparatus comprising: output process means for displaying a plurality of icons having respective pictograms; input means for selectively designating at least two of the plurality of icons displayed by the output process means, and generating input information corresponding to the designated icons; designated content-discriminating means for discriminating objects, their pictograms and roles corresponding to the at least two designated icons based on the input information supplied from the input means, wherein said designated content-discriminating means discriminates the roles of the objects corresponding to the at least two designated icons from a plurality of potential roles to which each object may correspond; transforming means for transforming the discriminated objects, their pictograms and roles into predetermined information, and outputting the predetermined information as designated-content information; designated-content memory means for storing the designated-content information; knowledge base means including pictogram knowledge attribute means for storing, as attribute knowledge, a functional role of each reference pictogram, and functional rule knowledge means for storing a plurality of functional rules each defining a function to be executed, on the basis of the reference pictograms and attribute knowledge; and function designating means for designating a function to be executed, on the basis of the relationship between the roles of the two objects corresponding to the at least two designated icons by using the designated-content memory means and knowledge base means.