In an electronic musical instrument 100, CPU confirms a pitch range of music stored in a music memory, and generates a keyboard image as large as possible for display based on marks M1 and M2 on a keyboard and the confirmed pitch range, and sends and displays the generated keyboard image on a television receiver 200, whereby a user is allowed to easily learn a relative relationship between a key position on a keyboard and a key position designated by performance guide in the keyboard image. The marks M1 and M2 are provided on the keyboard for indicating key positions corresponding respectively to reference pitches C4 and C5.