To surely close a balllike valve element 7 without catching a powder and granular material between the balllike valve element 7 and a valve seat 5 of a casing 4.

Although the powder and granular material is caught in between a rear fringe of an opening 9 of a communicating passage 11 of the balllike valve element 7 and a front fringe at a lower end of a guide cylinder 15 when the balllike valve element 7 is closed, the caught-in powder and granular material reaches a clearance 17 and flows freely therein, and it hardly receives a force that it enters toward the valve seat 5 together with the balllike valve element 7 when an upper part of the balllike valve element 7 sinks in toward the valve seat 5. As a result, the balllike valve element 7 can be surely closed without catching the powder and granular material between the balllike valve element 7 and the valve seat 5.