PURPOSE: To provide a branch pipe easily and at low cost from pipe material by combining bulge working and press working.

CONSTITUTION: A pipe material 1 of required diameter and wall thickness is cut in advance into a predetermined length. The pipe material 1 is subjected to boring by bulge working in its circumferential surface, then both ends of the pipe material 1 is flattened by press working into an oval shape, without deforming the hole 2 for bulge working. Plural core bars are inserted into each of the flattened oval ends at predetermined intervals, and press working is performed so that the flattened oval end area follows the circumferential surface of these core bars to form independent pipe-shaped branches 4.