A travel route display system executes a searching step of searching a database based on a given search condition; a numerical data calculating step of executing a predetermined calculation on a result obtained at the searching step to calculate numerical data displayed together with a travel route; an image data generating step of generating a plurality of kinds of image data for displaying the travel route on a screen, the generation being based on results obtained at the searching and calculating steps; a display image controlling step of so controlling the plurality of kinds of image data that an individual piece of image data or a synthesis of a plurality of image data can be displayed on the same screen, the plurality of kinds of image data being obtained at the generating step; and an image data displaying step of displaying the image data controlled at the controlling step.