Patent ID: 8561522

Claim:
A hydraulic cylinder that expands and contracts in accordance with supply and discharge of a working fluid, comprising: a piston unit that is defined in an interior of a cylinder tube to be free to perform a sliding motion within the cylinder tube; and a piston rod in which the piston unit is fixed to one end thereof and the other end thereof projects from the cylinder tube, wherein the piston unit is disposed on a small diameter portion of the piston rod such that an end surface thereof fixedly contacts a shoulder end surface of the piston rod, a round concave is formed as an annular concave in a base end portion outer periphery of the small diameter portion of the piston rod, a tapered portion is formed on an inner periphery of the piston unit from the end surface in alignment with the annular concave portion formed by concaving the small diameter portion, and a length of the tapered portion in a piston unit axial direction is equal to or greater than a length of the concave portion in a piston rod axial direction.