To allow adjustment of a tone quality of a keyboard musical instrument by utilizing the difference of mass.

A piano 100 includes leg parts 10a and leg parts 10b which are replaceable with the leg parts 10a and are different in mass from the legs 10a. A user replaces the leg parts 10a and the leg parts 10b to be able to adjust the total mass of the piano 100. Since the tone quality is varied when a load on a floor from the leg parts of the piano is varied, the tone quality of the piano can be adjusted by utilizing the difference in mass by replacement of the leg parts.