PURPOSE: To transmit the radio wave even when the transportation of objects in a pneumatic transportation passage is stopped by providing an opening part in a valve plate so as to ventilate the air at the opened position, and providing an air shut-off part made of synthetic resin to shut off the ventilation of the air at the closed position.

CONSTITUTION: A cylindrical body 1 is inserted in a pneumatic transportation passage, and mounted therein by aligning a passage 3 of the cylindrical body 1 to the pneumatic transportation passage. When an opening part 24 of a valve plate 23 is aligned to the passage 3 of the cylindrical body 1, an object to be transported by the pneumatic transportation passage can pass through the opening part 24 of the valve plate 23, and the radio wave can also pass. When an air shut-off part 25 of the valve plate 23 is aligned to the passage 3 of the cylindrical body 1, the object to be transported by the pneumatic transportation passage is shut off by an air shut-off part 25, but the radio wave can pass through and is transmitted through the shut-off part 25 because the air shut-off part 25 is made of synthetic resin. Thus, even when the transportation of the objects in the pneumatic transportation passage is stopped, the radio wave can be transmitted using the pneumatic transportation passage.