PURPOSE: To provide a compact and energy saving snow compaction device by introducing air-conveyed snow to a tank having a discharge gate on the lower end, providing a pressure applying plate for making horizontality at the time when it ascends and descends in the tank and pressurization is performed.

CONSTITUTION: A snow compaction device 6 is basically composed of a separation tank 10, a plate-like pressure applying member 26 for rising and falling in the tank 10, the discharge gate of the lower part of the tank, and an air conveying means 5 including the snow of the upper part of the tank, which is connected so as to separate air and snow in the tank 10. The plate-like pressure applying member 26 ascends and descends in the tank 10 by a carriage 27, and displaces to horizontal and vertical positions. The carriage is lowered in the case where a gate 17 is closed, and the pressure applying member 26 is made the horizontal position to pressurize snow. Thereby a snow compaction device can be obtained.