An electric wire outer cover is provided which is to be fitted around an electric wire and which has a tubular housing portion where the electric wire is to be housed, the housing portion being formed of a sheet, the housing portion being formed in a folded state. Further, walls forming the housing portion include a first wall having a projection formed therefrom and a second wall having a hole formed therein, and the housing portion is formed by engagement between the first wall and the second wall through melting of the projection that has passed through the hole and welding of the melted projection to the second wall.