PURPOSE: To bend a long-sized pipe for heat exchange easily in a short time to meandering shape by making all bending places to be bent at a time.

CONSTITUTION: Die mechanisms 20, 20a and wing mechanisms 25, 25a are provided respectively at equal intervals alternately to a pair of pantagraphs 25, 25a which are extended in parallel and elastic in the same quantity. The die mechanism and wing mechanism are arranged so that the wing mechanism of the other part of the pantagraphs 25a, 25 can be opposed to the die mechanism of one part of the pantagraphs 25, 25a. Further the 1st cam mechanisms 32, 32a projecting the die mechanism to the opposing side of the wing mechanism according to the shrinkage of the pantagraphs 25, 25a and the 2nd cam mechanisms 34, 34a moving the wing mechanism to follow the projection of the die mechanism are provided.