There is provided a graph display apparatus. An image display control unit causes a display unit to display the image data stored by the image and graph formula storage unit. An formula input unit inputs a graph formula according to a user operation. An input graph display control unit causes the display unit to display a graph corresponding to a graph formula input by the formula input unit, on the image data displayed on the display unit by the image display control unit as a background image. A model graph display control unit causes the display unit to display, in a different display mode, a graph corresponding to a model graph formula stored by the image and graph formula storage unit, together with the graph displayed on the image data as the background image on the display unit by the input graph display control unit, according to a user operation.