PURPOSE: To obtain a titled device capable of easily exchanging respective rolls when the change of pipe diameter is required by mounting a group of squeezing rolls, for lock-holding a blank material of electric welded pipe formed into a tubular shape, on a roll supporting plate and making the plate freely dismountable.

CONSTITUTION: In a squeezing-roll device of an electric welded pipe manufacturing installation for lock-holding a blank material, which is formed into a tubular strip by an inserting hole 31 formed by side rolls 32, a bottom roll 38, and top rolls 40, the side rolls 32 are mounted on a rectangular roll-supporting plate 27 through a U-shaped supporting frame 33, and the bottom roll 38 is also mounted on the plate 27 through a bottom roll supporting frame, and further the top rolls 40 for pressing both sides of a joining part of the material are mounted on a moving plate 41 made movable on the plate 27 in the horizontal direction. At the time of exchanging said respective rolls, fixing claws 28 and a vertically fixing claw 30 are unlocked, and the plate 27 and a group of the rolls are dismounted by lifting them in one body with the aide of a crane, etc., to mount a new roll-supporting plate together with a group of new rolls in a short time.