Damping device

A damping device comprising:

• a cylinder;
• a piston that is accommodated in the cylinder to be free to slide and divides an interior of the cylinder into a first working chamber and a second working chamber;
• a damping force generating element that connects the first working chamber and the second working chamber;
• a hollow portion partitioned by a free piston into a first pressure chamber and a second pressure chamber;
• a first connecting passage that connects the first working chamber and the first pressure chamber;
• a second connecting passage that connects the second working chamber and the second pressure chamber;
• a bypass passage that connects the first working chamber and the second working chamber;
• and
• a relief valve that is provided in the bypass passage and allows the fluid to flow from the first working chamber into the second working chamber when a differential pressure between the first working chamber and the second working chamber exceeds a relief pressure,
• wherein the piston comprises a piston main body that slides along the cylinder, the piston main body comprising the damping force generating element, a relief valve unit that is adjacent to the piston main body on a second working chamber side, the relief valve unit comprising the bypass passage and the relief valve, and a pressure chamber unit that is adjacent to the relief valve unit on an opposite side to the piston main body, the hollow portion being formed in an interior thereof.