PURPOSE: To eliminate space for fitting an O-ring, and shorten and make compact a core member by externally expanding and bending the top of the core member under pressure as a bent structure, and coupling the core member to a snap tap via the bend of the top as an adhesion structure.

CONSTITUTION: Regarding the installation of a snap tap 1 to turn on and off the supply of water to a pipe branched from the water main 2 of water service piping, the water main 2 is fitted with the snap tap 1, and a cap 17 is removed to keep a ball valve 15 in a released state. Furthermore, a water flow passage 21 is drilled through the water main 2 for communicating the upper release hole 18 of the snap tap 1 to the water main 2. Then, the valve 15 is closed to interrupt the supply of water, and an inserter 5 with an insertion lever 4 having a core member 3 fixed is engaged with a threaded section 45, thereby opening the valve 15. Thereafter, the lever 4 is pressed in the passage 21 of the water main 2 via a snap tap water flow port 11 on the operation of a pushing handle 55, and the top of the member 3 is bent with an inserting frontage flange 43, thereby being kept in close contact with the peripheral end of the port 11. Thereafter, the lever 4 is pulled out.