To provide a method for diagonal piercing rolling which is capable of averting the incorrect rolling and working hindrance of thick or thin tube stocks of an about middle extent and a diagonal piecing roll stand for this purpose.

This material to be rolled of an immediately previous tube stock end 4a is extruded under draft into the constricted part 10 of a mandrel bar 5 pushed in an axial direction, by which the thick part is formed at the material to be rolled. A mandrel bar of the diagonal piecing roll stand for diagonal piercing rolling the tube stock houses the material to be rolled within the region of the immediately previous built-up part in its rolling direction X and has the constricted part for rolling the tube stock end 4a having the thick part.