Chain

A chain is provided with components of a pair of inner chain joint boards which are oppositely configured; lining sleeves which are respectively inserted into the first through hole of each inner chain joint board in a manner that two ends project to outside of the pair of inner chain joint boards; pins which are inserted into the lining sleeves; a pair of outer chain joint boards which are configured in a manner of clamping the pair of inner chain joint boards from outside, wherein two ends of the pin are inserted into second through holes which are configured on the outer chain joint boards; and annular sealing components which are joined with two ends of each lining sleeve and are respectively configured between the outer surface of each inner chain joint board and the inner surface of each outer chain joint board. Inner peripheral side sealing rings are slidably connected with the outer chain joint boards in a manner that a first elastic ring in a compressed state is arranged between the inner peripheral side sealing ring and the inner chain joint board. Outer peripheral side sealing ring are slidably connected with the inner chain joint boards in a manner than a second elastic ring in a compressed state is arranged between the outer peripheral side sealing ring and the outer chain joint board.