PROBLEM TO BE SOLVED: To provide a spring suitable for a strong combination roll of long service life, capable of strongly working without loosening for a long time. SOLUTION: A first slot 15 and a second slot 25 are respectively opened on a front end 13 and a rear end 14 of the spring 7, the first slot 15 extends toward the rear end without reaching the same, the second slot extends toward the front end without reaching the same, the first slot separates two forward-facing laminae 27, 28 having ring-shaped end surfaces 19, 20, the second slot separates two forward-facing laminae 27, 28 having ring-shaped end surfaces 30, 31, the end surfaces 19, 31 axially protrude to the end surfaces 20, 30 of the adjacent lamina, and the protruding end surfaces 19, 31 are pressed to the end surfaces 10 of adjacent rings 6A, 3. When the spring is compressed, labyrinth-shaped spring force is generated between the end surfaces. COPYRIGHT: (C)2007,JPO&INPIT