To provide a repair work method which can easily and properly repair a separating and defective part while incidental work of excavating work or the like is reduced.

This repair work method, aiming at a coating layer 1A of a metal pipe 1 buried in the ground to be formed with the corrosion-proof coating layer 1A in an external surface, has at least a washing process washing in the vicinity of a damaged position 1B like a separating part or defective part generated in the coating layer 1A and a fusion process integrally fusing the total region of the damaged position 1B and its periphery in a condition that a sheet material 2, having a thickness equivalent to or larger than the coating layer 1A to be formed in a size capable of covering a total region of the damaged position and affinity to the coating layer 1A, is held to the damaged position 1B.