There are provided a bar-shaped piston rod having one end portion attached to a marine vessel propulsion machine main body; an inner cylinder; an inner piston mounted in the other end portion of the piston rod, is accommodated in the inner cylinder, and divides a space in the inner cylinder into a fourth chamber on the one end portion side and a fifth chamber on the other end portion side; an outer cylinder accommodating the inner cylinder therein; and an outer piston covering an opening portion of one end portion of the inner cylinder in a state where the piston rod is exposed, divides a space in the outer cylinder into a second chamber on one end portion side and a first chamber on the other end portion side, and is formed with a through hole that allows the fourth chamber and the second chamber to communicate with each other.
