To provide a water discharge joint surely preventing false water discharge by preventing a valve body from being opened even when pressurized fire extinguishing water is filled rapidly by virtue of a simple and miniaturized structure.

A joint body 12 includes a primary port 14, a secondary port 16 and a thermosensitive port 18 its one end mounting a thermosensitive decomposition part 28, and a valve hole 24 is formed at a position coaxial to the thermosensitive port 18 of a partition 22. A disc member 44 forms a valve body part 46 for opening and closing a flow path by inserting one end thereof into the valve hole 24, and forms at the other end an abutting part 50 abutting to the closing part of the thermosensitive port 18 by the thermosensitive decomposition part 28, and is held at an initial position by a spring 52. A first lift amount L1 from the initial position required for the valve body part 46 to open the valve hole 24 is set so as to be larger than a second lift amount L2 from the initial position required for the abutting part 50 to be abutted on the closing part of the thermosensitive port 18 and stopped by filling of pressurized fire extinguishing water on the primary port side.