The present invention provides a variable valve mechanism of an internal combustion engine which includes a main arm that is capable of swinging and that drives a valve when swinging, a first sub arm that is provided on one side in the lateral direction of the main arm and that swings when driven by a first cam, a second sub arm that is provided on the other side in the lateral direction of the main arm and that swings when driven by a second cam, and a switch device that performs switching between a first coupled state where only the first sub arm of the first and second sub arms is coupled to the main arm, and a second coupled state where only the second sub arm of the first and second sub arms is coupled to the main arm.