A graph display apparatus wherein a dynamic invention has the following arrangement. A dynamic graph key in a key input unit is operated by a user and a functional formula subjected to graph calculation and a change range and a change pitch of a coefficient value present in the functional formula input using numeric. symbol keys are stored in a formula register in a RAM (Random Access Memory). When an execution key is operated in a state wherein a coefficient change speed is stored in a register, the coefficient value of the functional formula is sequentially replaced within the change range at the change pitch. Graphic data of the functional formula and corresponding graph formulas with the changes in coefficients are sequentially stored in a plurality of video memory areas in a VRAM (Video Random Access Memory), and graphs and corresponding graph formulas for the changes in coefficients are sequentially read out in accordance with the coefficient change speed to be sequentially switched and displayed on a display unit. When the coefficient present in the formula is changed as a parameter, the graphs corresponding to the formulas are sequentially displayed, thus easily grasping the graph change state with the change in coefficient.