PURPOSE: To support learning of musical scale of movable Do by displaying the musical scale name of movable Do corresponding to the specified key in a musical score input device or a musical instrument.

CONSTITUTION: This instrument consists of a key setting section 1, a note input section 2, a note control section 3, a display device 4, an input control section 5, an input device 6 and a display reversing section 7. When a user specifies a change in the key by operating the device 6, the section 1 is operated, the key information is given to the section 2 and the musical scale name of the movable Do is shown on the piano keyboard picture being displayed on the device 4. Moreover, when the user selects an arbitrary note through the operations of the device 6, the section 3 is operated, the note selection information is given to the section 7 and the keyboard surface is inversely displayed.