PURPOSE: To provide a pipe which is laid smoothly along a wall surface, which is made of lead, being incorporated in a wash stand, a closet or the like, and from which a water drain or ventilating pipe is formed having a curve with a prescribed curvature, and being curved by using a core together with a rotary die, a gripping die and a press die.

CONSTITUTION: A pipe A made of lead has an inner diameter of about 30 to 60mm and a wall thickness of about 4mm, and has a curved part having a radius of curvature which is 1.5 to 2 times as large as the inner diameter of the pipe. With the use of a such a pipe A having a small curvature, a piping can be laid along a wall surface without deteriorating its appearance. A core 3 incorporating at its front end a synthetic resin cylinder 31 having at its front end an outer diameter equal to the inner diameter of the pipe A is inserted into the pipe A, and thereafter, the pipe A is clamped and fixed by a rotary die 12, a gripping part 15 and a gripping die 11 while the pipe A is slidably supported between the rotary die 12 and a press die 2, and accordingly, the gripping die 11 and the press die 2 are separated from each other by rotating the rotary die 12 so that the pipe is curved along the outer periphery of the rotary die 12.