A keyboard electronic musical instrument is of a type which comprises a keyboard including a plurality of individual keys for playing individual musical notes and arrayed in a first direction, and a key detecting device for detecting respective key depression velocities of the individual keys. The instrument further comprises an indicator device which presents a plurality of bar-graphic indications respectively for the individual keys in the keyboard, the bar-graphic indications being arrayed side by side in the first direction, each bar-graphic indication being elongate in a second direction which is perpendicular to the first direction and representing the key depression velocity of each of the individual keys. When a key is depressed, the key depression velocity is detected and the bar-graphic indication which corresponds to the depressed key is illuminated in green color with a length representing the key depression velocity. When performance data containing velocity data of the respective note is given, the bar-graphic indication of the corresponding key of the note is illuminated in red color with a length representing the velocity of the note.