A tennis racket having a racket frame defining a ball-hitting face, wherein if the upper part of the ball-hitting face is set as a 0-degree position, a string protection member is mounted on at least one portion of a head part of the racket frame in a range from a clockwise 45-degree position to a clockwise 135-degree position and in a range from a clockwise 225-degree position to a clockwise 315-degree position by interposing a viscoelastic member between the string protection member and the racket frame. The moment (Is) of inertia of the tennis racket in a swing direction is set to not less than 450,000 g/cm.sup.2 nor more than 490,000 g/cm.sup.2, when strings are not tensionally mounted thereon. The moment (Ic) of inertia of the tennis racket in a center direction is set to not less than 15,000 g/cm.sup.2 nor more than 19,000 g/cm.sup.2, when the strings are not tensionally mounted thereon.