To provide a high-pressure air cylinder valve excellent in durability by high precisely finishing a sliding part of a cylinder rod for sliding a packing for sealing outflow of operating fluid in a valve main body to a cylinder side.

A packing 21 is used for preventing fluid in a valve main body 15 from leaking to a cylinder 2 side. Since the resistance between a cylinder rod 12 and the packing 21 is increased with passage of time, it is necessary to consider abrasion of the packing 21 caused by chipping. High precision finishing is performed to the sliding part of the cylinder rod 12 by roller burnishing. In the roller burnishing, a small projecting part on the front surface of the sliding part of the cylinder rod 12 is crushed and embedded in a recessed part, the hardness is increased at the same time that the front surface is made flat, compressive force is made remain, and fatigue strength and abrasion resistance are therefore improved. Since a lubrication film having the several molecular layer thickness is formed in boundary lubrication, the direct contact of the cylinder rod 12 with the packing 21 is prevented, and friction and abrasion are decreased.