Located in Kang Koi district, the factory fire broke out at about 6.30pm and spread quickly to four warehouses storing fireworks.
More than 20 fire-engines rushed to control the blaze.
Provincial police chief Pol Maj-Gen Chalit Preechaharn said the factory belonging to Pacific Pyro Co, Ltd, which imports materials from China to produce and sell fireworks in Thailand.
Gen Chalit said that according to investigators the fire started in an office at the front of the factory before spreading to engulf warehouses.
The fire was under control by about 8.30pm and all four warehouses were destroyed.
Gen Chalit said the police need more time to investigate to identify the cause of the fire but initially believed that it was caused by accident.
He said the factory employed 65 workers but none were inside the warehouses when the fire broke out but.
One fire-fighter was injured when a warehouse roof collapsed.