To provide a method for repairing so that appearances of a projected corner section and an exterior wall siding can be sufficiently improved.

First of all, an insertable projected corner sheet metal 2 is vertically split along front edges of both right and left butt end pieces 4L and 4R, and both right and left front cover pieces 5L and 5R and a cover piece 6 are eliminated. And then, a projected corner sheet metal 10 is mounted across the front edges of both right side and left side exterior wall sidings 1 and 1. After then, tiling processing is performed on both right side and left side exterior wall sidings 1 and 1 and the projected corner sheet metal 10.