PURPOSE: To solve the problem that a throttle valve is made inoperable or operation of the throttle valve is made not smooth that is caused by the presence of a cutaway portion in a cylindrical sleeve of a throttle valve actuating link using double torsional springs, by forming a stopper portion for restricting radial displacement of a flange of a cylindrical collar at a flange portion of a dish-like collar retainer.

CONSTITUTION: In the drawing, a numeral 18 represents a stopper portion formed around the outer periphery of a flange portion 6 of a dish-like collar retainer 5 in the manner that it is projected in parallel with the axis of a shaft 3 of a throttle valve. The stopper portion 18 surrounds the outer peripheral surface of a cylindrical collar 7 with a small or a smallest clearance and restricts the radial displacement of the cylindrical collar 7 within a small or a smallest range. By the presence of this stopper portion 18, the outer surface of the flange portion of the cylindrical collar 7 and the stopper portion 18 of the collar retainer 5 are kept concentrical with each other, and concentrical cylindrical portions of a cylindrical sleeve 13 and the collar retainer 5 disposed coaxially with each other are kept concentrical with the cylindrical portion of the collar 7. Therefore, it is enabled to prevent the collar 7 from becoming eccentric tothe cylindrical sleeve 13.