PURPOSE: To enlarge combined use of a roll and to quicken a set up change by composing the device of a tilting jack devices for tilting upper roll holders, vertically movable pneumatic cylinders giving a supporting force to a vertically movable frame and roll holders and tilting pneumatic cylinders.

CONSTITUTION: A band plate edge forming roll device of welded tube is composed of a tilting jack devices 36A, 36B which tilts upper roll holders 16A, 16B under the support of traverse frames 27A, 27B, vertically movable pneumatic cylinders 39A, 39B giving a supporting force in the same direction as the forming reaction acting on vertically movable jack devices 36A, 36B under the support of a stand 21 to a vertically movable frame 23 and tilting pneumatic cylinders 41A, 41B giving a supporting force in the same direction as the forming reaction acting on the tilting jack devices 36A, 36B under the support of a traverse frame to upper roll holders 16A, 16B.