PURPOSE: To prevent an injection port of pressure air from choking of sand in a sanding device for a railway by adopting a structure to be opened and closed as providing near it a butterfly valve to adjust the amount of sand.

CONSTITUTION: When a cock of a sanding device is operated in an operator's room, pressurized air is supplied within a siaphragm 18 of a nozzle 11' via an air pipe 8', a supply port 9, and an air port 16, and a valve body 19 is shifted downward to open an injection port 17. Consequently, the sand in a sand box 1 is drawn out by the injected pressurized air to be sprayed on a rail 15. In this construction, since the injection port 17 is opened only when the pressurized air is injected, there is no possibility of entering of sand into the injection port at a usual time. Besides, the amount of sand drawn out from the sand box 1 is adjusted by turning the butterfly valve 21.