The present invention relates to a frost preventing apparatus. In order to achieve the above purpose, the present invention comprises a rotation device, a fan part, and a hot-air unit. The rotation device comprises: a base shaft including a base installed on the top end of a pillar, and an insertion hole formed in the upper side inside of the base, wherein the insertion hole is used to insert a wire into the base a rotary gear positioned above the base shaft a slip ring combined with the upper side of the rotary gear and having a terminal provided on an external circumferential surface a carbon brush having a terminal provided on one surface thereof, wherein the terminal of the carbon brush interacts with the terminal of the slip ring to be in contact with the terminal of the slip ring a power breaker connected with the carbon brush through a connection line a driving motor positioned below the power breaker to receive power from the power breaker a driving gear connected to a shaft of the driving motor, and engaging with the rotary gear in a corresponding manner and an external body in which each of the components are installed. The fan part is mounted on one side of the external body of the rotary device. The hot-air unit is positioned below the rotary device, and connected and fixed to the pillar to supply hot air. As described above, the present invention includes the rotary device which rotates a fan at 360 degrees without twisting the wire, and the hot-air unit which is provided below the rotary device, so the present invention can primarily prevent the frost of crops by ventilating high-temperature wind which is formed in an inversion layer by operating the rotary device and can completely prevent the freezing and frost injury of crops by secondarily supplying hot air to the inverse layer using the hot-air unit to ventilate the hot air to the crops when the temperature rapidly falls by the environment.COPYRIGHT KIPO 2016본 발명은 서리방지장치에 관한 것으로서, 상기 목적을 달성하기 위한 본
