Firefighters from Staffordshire Fire and Rescue Service were called to the field off Congreave Lane, Congreave, just before 5.50pm yesterday.
Crews from Brewood, Cannock, Penkridge, Rising Brook and Stafford attended the scene, where they found the farm machinery well-alight.
The fire was contained to the combine and crews worked to prevent the fire from spreading to nearby standing crop.
A total of four pumps, a water carrier, two breathing apparatus and two hose reel jets were used to extinguish the fire.
No one was reported injured and the cause of the fire was later deemed to be accidental.
Crews left the scene at 12.30am on Friday.