A piano roll score, a word input/edit area and a word continuous display area are displayed. Note bars corresponding to notes of a melody are displayed on the piano roll score. The word input/edit area is divided into input cells having a length corresponding to a tempo number of each note. A pointer is moved to the input cell and a mouse is left-clicked to display an editor area. A letter(s) or character(s) is input by using a word processor function. The pointer is moved to the input cell and the mouse is right-clicked to display a command select box. A display command is selected from the command select box and input, the display command controlling a display style of a song-word character train in the word continuous display area. A dictionary database is used to search a song word by using the number of syllables and a part of speech as search keys. A sentence syntax is selected by using a sentence syntax template.