Abstract: An electric contact actuating mechanism for an automatic door comprising a rotary operator having a rotary shaft and interlocked with a door-driving device, a desired number of working arms fitted on the rotary shaft of the rotary operator so that they may be separately rotated relative to the rotary shaft when the rotational force applied thereto exceeds a predetermined value, working elements mounted on the respective working arms, responsive switch elements provided on a base member so that they may be actuated when the working elements approach thereto, and a stopper provided on the base member for stopping the rotation of the working arms; and thereby enabling the adjustment of its electric contact to complete by one shuttling operation of the door when installed.