The present invention relates to a movable lift device including an overturn preventing system that uses variation in the center of gravity when rotating a bed unit where a user is laid down to prevent a movable lift device from overturning, which includes a base frame defining a bottom surface an upper structure comprising a post rotatably upwardly extended from the base frame a predetermined length and a bed unit supported by the post, being horizontal with the bottom surface to enable a user to lie down, wherein the bed unit is rotatably provided with respect to the base frame and an overturn preventing control unit for controlling the height of the bed unit with respect to the base frame based on the rotation of the bed unit.
