PURPOSE: To provide rotor blade operating mechanism capable of transmitting a rotor blade opening/closing command, transmitted from a rotor blade drive unit, to a transmission shaft by rotational displacement in an axial fan.

CONSTITUTION: In rotor blade adjusting mechanism, a rotor blade opening command transmitted to an external link 2 from a rotor blade drive unit 1 is transmitted as the rotational displacement of a transmission shaft 4 to the interior of a fan through a lever 3. The rotational displacement is converted into linear displacement to an oil guide valve 6 by an internal link 5. The oil guide valve 6 is thereby switched to move a hydraulic cylinder 7, and a rotor blade 14 is rotated through an arm 13. The lever 3 has the function of transmitting the command from the external link 2 as the rotational displacement to the transmission shaft 4, and the lever 3 is formed of two springs, an opening side ring, a closing side ring, and the like.