PURPOSE: To decrease frictional resistance between a projecting die part and cylinder peripheral wall and to avoid a galling on the projecting die part, etc., and a crack on a cylinder bottom, etc., by constituting the projecting die part provided at a die of a roller.

CONSTITUTION: When each recessed die part of a punch 11 coincides with each roller 27 of a second die 15 by descending an upper die 9, and each projecting die part 19 of the punch 11 coincides with each recessed die part of the second die 15, the outer peripheral part of a bottom wall 3 and the lower part of a peripheral wall 2 are pushed in the inside in a radius direction advancing each recessed die part 21 of the punch 11 by each roller 27. In this way, the forming of an outward recessed line 5 and that of an inward projected line 20 are started. When the peripheral wall 2 of a cylinder 1 passes each roller 27 by further descent of the upper die 9, the forming of each outward recessed line 5, etc., is completed. Since each roller 27 is rotated centering about a supporting shaft, the frictional resistance between each roller 27 and the peripheral wall 2 can be remarkably decreased, and the galling on each roller 27, etc., and the crack of the bottom wall 3, etc., can be avoided.