The invention discloses a cutter inclination and turning mechanism applied to a cradle-free spiral bevel gear milling machine. The cutter inclination and turning mechanism is characterized in that: an installation flange is eccentrically fixed on a cutterhead driving rotary drum; the axial line of the installation flange is deflected from the direction of the axial line of the cutterhead driving rotary drum; an angle alpha less than 90 degrees is formed between the two axial lines; a cutter inclination body is fixed on the installation flange; the cutter inclination body is provided with an inner installation end face matched and connected with the installation flange, and an outer installation end face for installing a milling cutter installation disc; and an angle between the axial lineof the inner installation end face and the axial line of the outer installation end face is alpha, so the inclination angle of the axial line of the milling cutter installation disc can be adjusted between zero and twice alpha. The cutter inclination and turning mechanism has a simple structure and is convenient to adjust; by the cutter inclination and turning mechanism, the machining range of the conventional numerically controlled cradle-free spiral bevel gear milling machine is extended effectively; under the condition of no cradle mechanism, an arc-tooth bevel gear or a hypoid gear can bemachined by a human friendly transduction (HFT) method (a large-wheel forming method or a small-wheel cutter inclination method); the production cost of the lathe and the manufacturing cost of the gear are reduced; and the cutter inclination and turning mechanism can be widely applied to gear machining industries, particularly driving and driven bevel gear machining of automobile driving bridges.