To realize a water supply port for a connection water supply pipe which is difficult to break and close the connection water supply pipe.

This water supply port 10 for a connection water supply pipe for introducing fire-distinguishing water supplied through a water supply pipe from a fire-distinguishing pump to a connection water supply pipe 3 for distinguishing fire installed in a building 1 comprises a tubular body 11 having an opening part 16 for inserting the water supply pipe; an annular member 12 installed on a peripheral edge of the opening part 16; an annular holding member 13 detachable to the body 11 for holding the annular member 12 between it and the body 11; a cover body 14 detachable to the opening part 16; and a connection string 15 connecting the cover body 14 with the annular member 12. When the cover body 14 is detached from the opening part 16, it is hung near the body 11 by the connection string 15.