A piston of a fluid pressure cylinder comprises a sealing ring interposed in a sealing ring accommodation groove, a piston ring that is interposed in a piston ring accommodation groove of the piston and comprises a fractured portion, and a backup ring that is attached to an outer peripheral surface 45 of the piston 4 and contacts the sealing ring and the piston ring. A groove for holding the backup ring is not required, and therefore a diameter of the piston can be reduced relative to the sealing ring. As a result, attachment of the sealing ring to the piston is simplified.