An electronic catalogue system which, for easy sensory recognition of the size of a commercial product which is displayed in an electronic catalogue, displays on one screen the image of the commercial product together with the image of an article for comparison which is for comparing and notifying the size comprises: a communication control part which reads three-dimensional data DTA regarding the commercial product and three-dimensional data DTB regarding the article for comparison; an observation image generating part which generates the image of the commercial product and the image of the article for comparison based on thus read three-dimensional data DTA regarding the commercial product and three-dimensional data DTB regarding the article for comparison; and a displaying part which displays the generated images.