1. An operation guidance generating unit for generating guidance image data to create animated guidance images explaining an operation procedure of a data processor on a screen of a display unit, the operation guidance generating unit comprising: a guidance description means describing the operation procedure for updating guidance images, thus enabling a user to operate the data processor; an object data storage means including means for storing image data for each element necessary to generate the guidance images on the screen of the display unit and a graphic display processing means for editing image data; a style rule storage means for storing display format data for an image area where a display format is amendable, the area being included in the guidance images; and a guidance data generating means for generating the guidance images by selecting certain image data from the object data storage means in accordance with each procedure described in the guidance description means and subsequently using the graphic display processing means to edit the selected image data based on the display format data stored in the style rule storage means.