Abstract: An improved method for producing a protective-coated steel pipe in a construction work site by spirally winding and melt-bonding a belt-like thermoplastic synthetic resin sheet around the outer peripheral surface of a steel pipe, for use as a construction member in corrosive circumstances, the method provides a winding step winding the sheet around the outer peripheral surface of the steel pipe while contacting adjacent side end faces of the sheet in a face-to-face relation to each other and a bonding step of heat melt-bonding the adjacent sheet portions to each other in the contacted state of the respective side end faces while pressing both sheet portions together by a pressing means when they begin to melt. Also disclosed is an equipment used for practicing the said method. According to these method and equipment, the resin of the sheet comes into completely close contact with the steel pipe so the corrosion resistance of the pipe is improved remarkably.