There is provided an apparatus for displaying musical score data in a display area. In the apparatus, a specifying device specifies a display range of original musical score data. An extracting device extracts musical score data included in the display range from the original musical score data and extracts musical information precluded from the display range but influencing the extracted musical score data from the original musical score data. A determining device determines whether a supplementary display is necessary or not in accordance with the specified display range. A setting device divides the display area into a main display area and an auxiliary display area when the supplementary display is necessary. A display device displays the extracted musical score data in the main display area and concurrently displays the extracted musical information in the auxiliary display area. The display area may be divided into a plurality of display sub areas. A display format is specified for each of the display sub areas in accordance with setting of the division of the display area. The original musical score data is processed to generate musical score data compliant with the display format.