The present invention provides a variable valve mechanism which includes a rotating cam provided on a camshaft, a swing arm that contacts with the rotating cam to swing, a drive arm that drives a valve in conjunction with the swing arm, a variable arm that turns the drive arm around a swing axis of the swing arm, an actuator that drives the variable arm, and cam device that is provided between the swing arm and the drive arm. The variable arm is provided so as to be able to rotate relatively around the same axis as the swing arm, and the cam device changes the initial position of the drive arm with respect to the swing arm accompanying the turning of the drive arm.