A guitar synthesizer has a guitar body (10) and a synthesizer portion (20). The body (1) of the guitar extends toward a head (3) in a direction so that an end (11) serving as a first vibratory member in the body base to which a neck (2) is connected, intersects with the neck. A second end (13) serving as the second vibratory member may also intersect with the neck. A non-vibratory portion (12) is interposed between the first and the second vibratory members (11, 13). A reinforcing frame (4) is attached to the head and body to interconnect them with the shortest distance for providing a firm connection from the non-vibratory portion of the body to a part of the head closer to a nut (5) than to the head end. Thus, the connection between the head and the frame is located below the central point of the distance between the nut and the top end of the head. Such a structure suppresses vibrations of the neck and an early attenuation of the fundamental frequency due to the vibration of the strings (7), are avoided.