To equalize the load applied to two electric actuators.

Actuator rods 16 of the two electric actuators 2 and 3 are fixed to a balance member 6 with pins, the balance member 6 is fixed to a connection frame 7 in its center part by a supporting pin 15, and the connection frame 7 is fixed to a bracket 14 of a link 4 by the pin, and expansion and contraction of the electric actuators 2 and 3 drives the link 4 through the balance member 6, connection frame 7, and bracket 14. Even when variation in the driving length of the two electric actuators 2 and 3 or the difference in the load occurs, the balance member 6 is rotationally displaced around the supporting pin 15, and the load of the two electric actuators 2 and 3 is balanced, and the load is equalized.