To make a corrosion proof function for a second pipe body complete when a first pipe body is connected to the second pipe body by way of a connector.

A protection ring 30 made of nylon is bonded to the pipe widening flange part 28 of a second pipe body 18 in such a way that a circumferential wall, at the opposite side to the direction that the second pipe body 2 is inserted, can be covered. The second pipe body 18 is gradually inserted into a connector 10, and when its pipe widening flange part 28 is inserted into a housing hole 16 against the elasticity of a pipe body slip-off preventive fixture 26, after click feeling has been obtained when the pipe widening flange part 28 passes through the pipe body slip-off preventive fixture 26, the protection ring 30 bonded to the pipe widening flange part 28 abuts against the projection of the pipe body slip-off preventive fixture 26, and they are engaged with each other, so that the connection of the first pipe body 14 with the second pipe body is thereby completed. Under this condition, what the pipe body slip-off preventive fixture 26 is brought into contact with, and is engaged with, is the protection ring 30 made of nylon, and the aforesaid fixture will never be in contact with the surface of the second pipe body that is plated for corrosion protection.