Abstract: A bow musical instrument in which at least the front (1) is constituted by a thin wall of composite material comprising at least two superposed sheets (A, B, C, D, . . . ) of crossed and directed long fibers, the wall being covered on at least one of its faces with a lining material (Y, Z) of considerably lower density than the fibers, wherein the deposition of the sheets of fibers is such that the ratio of the longitudinal modulus of elasticity divided by the transverse modulus of elasticity of the wall is higher in a wall zone close to the longitudinal axis of symmetry of the instrument than it is for a zone close to the sides of the instrument.