PURPOSE: To simply form the metal adhesion coating by melting having a uniform thickness on the inner face of steel tube, by purifying the inner face of long length fine diameter steel tube and sealing both end parts after inserting the rod material, powder, foil etc. of metal for covering and then, heating at a temperature of melting point or more of inserted metal.

CONSTITUTION: Wire rod, powder or foil used as metals for inner face covering, such as Sn, Pb, Zn or these alloys, are inserted into the steel tube after carrying out degreasing and rust removing treatment of the inner face of long length fine diameter steel tube. The above tube is heated at 700W1150°C in the furnace of non- oxidative gas atmosphere after crushing and sealing both ends of the tube by the press processing etc. As a result of it, air in the tube is expanded and is vomitted from sealed part to outside by the expansion successively. The metal is stuck by melting and is extended on the inner part of the steel tube by the above vomitting in the condition of high vapor pressure by a dilute air pressure in the tube. Adhesion film by melting of molten metal having a uniform thickness, is formed on the inner face after cooling.