PURPOSE: To reduce remarkably the generation of specks such as pits or eruption by forming a center hole which satisfies a prescribed condition at the center of the rear-end surface of a billet before piercing, in a Mannesmann pipe manufacturing method.

CONSTITUTION: In a Mannesmann pipe manufacturing method, a center hole 15 of circular conical-shape is formed in a hot state at the center of the rear-end surface 13a of a billet 13. And the hole 15 is formed into a continuously circular conical-shape from the rear-end surface 13a of the hole 15. Further, the hole 15 is formed so that the diameter (d) of its bottom surface is 30mmW a plug diameter and the circular conical angle θ is 40W100°. In this method, the generation of earing 3 is prevented and the generation of pits and eruption are reduced.