PURPOSE: To control the diameter of a circular pipe upon resuming of molding after interruption in the midway of molding and to enable the remelting of the joint, by providing an adjusting roll which can move the circular pipe to a die in the forming part of molten metal by an electroslag melting method.

CONSTITUTION: The solidified metal part 8 after rotation at one turn is moved in the direction of an axial center 6 by means of inside and outside rolls 3, 4 provided to a water-cooled copper die 1 in the forming part of molten metal so that an ordinary radius R for forming the molten metal having a difference between the solidified metal part 9 after rotation at two turns and an allowance (d) for shrinkage of a joint is made at the position of the forming part 7 of molten metal when the molding of a circular pipe is interrupted on the way of molding by inserting a start piece 13 mounted to a rotary table 12 into the die 1, penetrating the molten metal therein and pulling the molten metal while rotating the table 12 around the center 6. The table 12 is formed movably eccentrically with respect to the movement of the part 8 by the above-mentioned operation and the movement in the vertical direction of the product is supported by a roll 10 with vertical adjustment, whereby the interference in the rotation of the table 12 is prevented.