PURPOSE: To anticorrosively coat the end of a resin coating tube with a specific thermal fusible coating member simply and effectively in a short time by mounting the member on the cut part of the tube material and thermally fusing the member.

CONSTITUTION: A member 17 to be coated which is made of a thermally fusible adhesive film (e.g., polyethylene series hot melt agent film) and which has a cylinder 21 having an outer peripheral surface 19 of the outer diameter equal to the inner diameter of the inner peripheral surface 3 of a steel tube 1 to be mounted and a collar 27 having an outer diameter equal to that of the end surface 13 of the tube 1 and to be connected to the end of the cylinder 21 is cused. In other words, the member 17 is inserted to the cut end of the tube 1 provided with a resin coating layer 5 on the inner peripheral surface 3 to contact the end surface 13 of the tube 1 with the surface 25 of the collar 27 of the member 17, is then heated to fuse the coating member to drape the member with the layer 5, and is then cooled to be solidified, thereby coating the cut end of the tube 1. Subsequently, the tube is connected through a tube joint 31 to the other steel tube 45.