To provide an assembly structure of water faucet parts capable of removing a packing from the screwing part even if a screwed side member (a first member, for instance) forms the inside space as a water passage, and hardly bring a trouble of "breakage, strain, etc." in respective members (at least one of the first member and the second member).

A first member (a front end metallic fitting, for instance) 20 having a female screw 2b and a second member (delivery head, for instance) 30 are inserted into a through hole 35 and assembled together by a screw member M screwed to the male screw 2b to form the assembly structure of a water faucet. The female screw 2b is installed in a screw part 24 to be screwed of the first member 20 and the screw part 24 is installed in a decentered position from the water passage way of the first member 20, the inside of the screw part 24 is isolated from the first member 20.