PURPOSE: To provide a method for forming an excellent pre-neck-in part and pre-flange part with a roll form method.

CONSTITUTION: The bottom of a seamless can 4' having a pre-neck-in part 4'g and a inverse trapezoid like pre-flange part 4'h is fixed, in a state of abutting the internal face of a neck part 4'f to a cylinder part 32b of a re-flange die 32, a trapezoid like front machining face and a reform stand 29 having a rear machining face are advanced, the neighborhood of a curve part 4'd is pressed to the inward direction of radius, and the curve part is deformed plastically so as to be along the reform die. Next, the reform die is retired in a small amount and the neighborhood of the curve part is made to be a reversed bowl shape like. The re-flange part is advanced in this state, the pre- flange part 4'h is pressed to the re-flange face of the re-flange die, and the flange part in the radius direction is formed.