PURPOSE: To enable design of a vane of the optimum shape dimension and to improve effect of thrust vector control by manufacturing the rotary shaft of vane of a shape memory alloy, which bends at room temp. and becomes the straight line state at high temp. in the thrust vector control apparatus for rocket motor.

CONSTITUTION: The thrust vector control apparatus for rocket motor is formed with a servo device 6, rotary shaft 7a and the vane 8A, and the rotary shaft 7A is manufactured of the shape memory alloy (Ti.Ni series alloy, etc.), which bends at the room temp. and becomes the straight line state at high temp. In this constitution, at the time of igniting thrust chemical 3 in a combustion chamber 2 in a barrel body 1, the pressure in the combustion chamber 2 is raised to blow off nozzle closure 5 and combustion gas is passed through the nozzle. Therefore, the rotary shaft 7A is heated to become straight line state and the vane 8A reaches the prescribed position in the gas flow to execute control with a servo device 6. By this method, the vane 8A can be made to the optimum shape dimension without colliding against the nozzle closure 5 and the thrust vector control is effectively executed.