To easily input and display a character expressing an atomic symbol.

A periodic table managing table 24a is prepared for registering the correspondent relation of each element to the other element based on the arrangement of periodic table of element. When a symbol expressing any element is inputted from a key input part 12, a CPU 10 discriminates the other element in the correspondent relation with this element by retrieving the periodic table managing table 24a based on the element corresponding to the inputted symbol. Then, the CPU 10 displays the symbol expressing this discriminated element on a display part 18 corresponding to the correspondent relation with the symbol inputted by the key input part 12.