PURPOSE: To obtain a metal pipe without surface defect by holding temp. of a wall face coming into contact with molten metal to solidifying temp. of the metal or higher and making formation of the surface solidified layer of the casting tube the flat face ro the projecting face at the outlet face of the mold at the time of casting the metal pipe with the hollow outer mold and core mold.

CONSTITUTION: The mold A is formed of the outer mold 1 and the core 3 and both are composed of refractory material of graphite, etc., respectively and electric resistant exothermic bodies 2, 4 of nichrome wire, etc., are included as built-in. A dummy tube 5 plugs the outlet of the mold at the time of starting the casting and is cooled with cooling medium injecting from the spray nozzle 6 to cool the molten metal, and the metal pipe 11 is descended. The surface layer in the molten metal starts to solidify at just below the outlet of the mold and pouring temp., height of molten metal surface, drawing speed, wall surface temps. of the outer mold and the core, cooling speed of the pipe, etc., are controlled so that the solidified interface at the outlet face forms almost the flat face or the projecting face from the outlet toward the inner part. By this method, the metal pipe having smooth surface at inner and outer faces without any surface defect can be easily and efficiently obtd.