A step apparatus for heavy construction equipment and tree harvester having a leveling system for controlling a horizontal level of a cab and an upper frame is provided, which includes a step protector including a main body fixedly installed on one side of an upper frame, a step guide hole opened from an inside of the main body to an outside, a guide rail formed along a length direction of an inner side wall of the main body, and an insert hole formed on one side of the guide rail and open toward a vertically upward direction of the guide rail; a side step including a plurality of foot steps arranged at specified intervals on a step frame to form stairs, a step drawer formed on an upper part of the step frame and seated in the step guide hole, and a guide pin positioned adjacent to the step drawer and projected toward the side wall of the main body, wherein when the guide pin is slid along the guide rail, the step frame is seated in the main body or is drawn out from the inside of the main body; and a folding actuator including a cylinder rod coupled to the step drawer to be extended and contracted, the folding actuator drawing the step drawer to the inside of the main body of the step protector.