To surely hold a condition corresponding to each of a stored condition of a key board, a using condition thereof and a condition thereof at the time of transportation, without damaging the key board, and to keep a grade as a key board musical instrument.

In this electronic key board musiacl instrument, a key board 4 is drawn out frontwards from a key board storing part 6 upto a key board- drawn-out position at the time of usage to conduct a musical performance, the key board 4 is stored in a rear side upto a key board storing position of the key board storing part 6 at the time of non-usage, and the key board 4 is fixable at the key board-drawn-out position and the key board storing position respectively.