A control section analyzes sound data to acquire data indicative of a plurality of attributes, such as pitch and volume, and displays, on a display screen, graphics indicative of the acquired pitch and volume. At that time, the control section displays, on the display screen, a pitch curve where a value of pitch is represented by the vertical axis while the passage of time is represented by the horizontal axis. Also, at a position on the display screen based on a displayed position of the pitch curve, the control section displays a volume graphic where a level of volume is represented by a length or distance or width, in the vertical-axis direction, of the volume graphic.