A stringed musical instrument including a body in which a cutaway is formed, wherein the body includes a back board on which at least one brace is provided so as to extend in a width direction of the back board, and wherein a first brace, which is the closest to the cutaway among the at least one brace, has a dimension in the width direction of the back board smaller than a width of the back board at a position of the back board at which the first brace is fixed, the first brace being fixed to the back board so as to be disposed nearer to one side of the back board than another side thereof on which the cutaway is formed.