To provide a device for obtaining tones of good quality by preventing oscillation of a resonant plate of a guitar from being damped with an arm when playing it.

The solution is obtained only by preventing the resonant body of the guitar from being pressed between the right breast and right arm, and if the resonant body part is covered by a protector so that the playing right arm does not touch the resonant body, the resonant body resonates with oscillations of the strings with fidelity, and music can be performed in tones of good quality and larger sound.