On arrival they confirmed the barn was well alight and that fertiliser was also involved in the fire.
A further two appliances from Modbury and Totnes were sent for and crews attacked the fire using two main jets, one hose reel jet and with two firefighters in breathing apparatus.
The environmental protection unit was also sent from Newton Abbot and breathing apparatus wearer increased to four.
A fire officer from Modbury said: “On arrival at Kingsbridge we were immediately mobilised to attend a combine harvester fire as more crew members were required to assist Kingsbridge and Dartmouth already in attendance.
“The combine was well alight within an agricultural building.
The access was up a narrow lane and Modbury along with Totnes were needed to help extinguish the fire, prevent escalation and stop water run off.”
The blaze was caused by accidental ignition and totally destroyed both the barn and the combine harvester, a Devon and Somerset Fire and Rescue spokesman said.
He added: “Steady progress was made attacking the fire. Breathing apparatus was reduced, with the introduction of a fog spike attack on the fire.
“A thermal imaging camera was also used.
“The fire was extinguished and duty of care was handed back to the owner.
“The cause of the fire was deemed as accidental ignition and totally destroyed the barn and the combine harvester.
“A total of six breathing apparatus, two main jets, one hose reel jet, two triple extension ladders, one thermal imaging camera and one mini ejector pump was used.”