To always obtain an excellent seal property by providing the gate mechanism with a port reciprocating between the faced valve seats around a through conduit and constituting so as to press the outside seal surface to the valve seat through the wedge operation between both by the relative movement of the gate and segment in this mechanism.

This stem rising type through conduit gate valve has a valve main body 10 provided with an inner chamber consisting of an upper camber 12 and lower chamber 14. Mutually parallel valve seats 20, 22 are provided on the intermediate part of the valve main body 10 formed ports 16, 18 on the common axis. A stem 34 installed to a gate.segment assembly 30 is extended through a cover 32 for forming the upper part of this valve main body 10 and this is elevated by the turning operation of the valve operation tool of a hand- powered wheel 28. The assembly body 30 is composed of the movable gate 36 and segment 38 with double taper and they are expanded by the relative movement and push-pressed and stuck to the valve seats 20, 22 at the valve closing position.