PROBLEM TO BE SOLVED: To solve problems in that in a conventional method of water spraying for preventing freezing, even though its automated valve for spraying water, equipped with a prescribed temperature-actuating valve has a function of staring the water spraying when it becomes a temperature for falling frost, it is not equipped with the function of stopping the water spraying when the temperature rises after the starting of the water spraying and there is no fear of freezing and frost damage, and therefore there is an inconvenience that the water is sprayed uselessly unless the spraying is stopped by hand, and also there is a shortcoming that it is necessary to maintain the prescribed temperature- actuating valve periodically since it has an inferior sensing accuracy and further changes considerably with time. SOLUTION: This freezing and frost damage-preventing device prevents the freezing and frost damage by starting the water spraying when the ambient temperature falls and the output of a temperature sensor for detecting the temperature of a field agrees with the water spraying-starting temperature, and stopping the water spraying when the temperature rises and agrees with the previously set water spraying-stopping temperature.
