<p>A metal pipe melt-coated with a thermoplastic synthetic resin using an adhesive composition which contains as major components 5-50 parts by weight of an oil-soluble phenol resin, 5-60 parts by weight of an ethylene copolymer and 5-50 parts by weight of a petroleum hydrocarbon compound having a mean molecular weight in the range of 50,000 to 1,000,000.</p>