To provide a lubricating device and method capable of lubricating a piston or a cylinder of a large engine as efficiently and simply as possible at a low lubrication ratio.

This piston for the cylinder of the large engine includes a piston barrel 34 having a storage chamber 5 to receive lubricant. The piston barrel 34 is narrowed by a piston skirt 16. The storage chamber 5 is connected to the piston skirt 16 via a lubricant passage 10 and includes a feed unit 7 constituted to be attachably/detachably connected to a lubricant source 2. The feed unit 7 is opened in the storage chamber 5, and the lubricant passage 10 is opened in a lubricant collecting element 14. Further, a lubricating device and a lubricating method are suggested.