Patent ID: 7343849

Claim:
A cylinder apparatus comprising: a guide mechanism for guiding displacement in an axial direction of a piston provided in a cylinder tube, said guide mechanism including a guide hole formed in said cylinder tube, and a guide rod provided insertably into said guide hole to make displacement integrally with said piston; a pair of holes which makes communication between said guide hole and outside of said cylinder tube and which discharges air from inside of said guide hole or which sucks said air from said outside of said cylinder tube into said guide hole in accordance with forward and backward movement of said guide rod; and an intake/discharge tube which is connected to said hole and through which said air flows to be sucked into or discharged from said guide hole via said hole, wherein a pair of said guide holes is provided substantially in parallel to a cylinder chamber in which said piston is arranged, said cylinder chamber being positioned at the center between said guide holes, and one guide hole and the other guide hole are communicated with each other via communication passages, and wherein said intake/discharge tube is designed to have a length such that an open end of said intake/discharge tube is capable of being arranged outside an environment in which water exists, when said cylinder apparatus is installed in said environment in which water exists.