Abstract: A guitar comprising a neck truss rod supporting construction capable of firmly coupling its elements, such as a fret board, a neck, a guitar body and a front board of the guitar body, with one another. The neck truss rod supporting construction includes a truss rod supporting member, an extension member providing a wide bonding area and a coupling member having a cross-sectional shape of a trapezoid rotated 90.degree. and engaged in a block of the guitar body in a dovetail manner. The extension member has upper walls extending transversely and defining recesses among them. The front board of guitar body also has an opening engaged with the upper walls of extension member in a fit manner. At upper surfaces of the truss rod supporting member and the extension member, a plurality of longitudinal shallow slots are formed to provide positive bonding surfaces.