A plurality of strings are stretched over a frame, constituting an overall framework of a body of a piano, with their respective rear-end engaging rings engaged by corresponding pins provided on the frame. There is also provided a string-bounding preventing member that, in case any one of the strings snaps or breaks, prevents the broken string from disengaging from the corresponding pin to bound violently away from the pin. The string-bounding preventing member is, for example, a strap member that is passed through the respective engaging rings to thereby connect together the strings. The string-bounding preventing member allows the broken string to be left connected with the other strings and hence stay in place on the frame without bounding.