To provide a pipe joint having a water stop structure for preventing leakage due to excessive fastening of a screw in connection between a water supply pipe and a sprinkler head, and to provide the sprinkler head connectable to the pipe joint or to a pipe joint in general use, as well.

The water supply pipe joint 10 having a female screw 14 comprises an annular water stop member 15 provided between the female screw 14 and the terminal end of the water supply pipe joint and a step part 17 provided near the female screw 14 for contacting the sprinkler head 20 at its front end. The sprinkler head 20 has a contact face on a cylindrical portion 21 of the female screw 22 for contact with the annular water stop member 15.