The fire burned through a grass field covering about 320,000 square metres on Rangsit-Nakhon Nayok 17 Road in Prachathipat sub-district at about 2.30pm.
Flames spread rapidly and bore down on a community and Bhanjob Rak School in Bhanjob Rak Road. Teachers swiftly evacuated the screaming children from the school as flames licked the walls and a building.
Local people raced to save their possessions as smoke blocked visibility on Rangsit-Nakhon Nayok Road.
More than 10 fire engines from Rangsit municipality were brought in to fight the fire. It took firefighters about two hours to put out the blaze.
Villagers said the grass field had caught fire two days ago and had been put out. However, it simply restarted Wednesday afternoon.
Firefighters said grass fields easily caught fire in the hot weather and because of garbage burning. They said it was difficult to put out grass field fires as they can easily reignite.