Fire, police, ambulance and air ambulance crews were called to The Street, in Patching, at around 5pm.
The man had been repairing the small tractor when it moved and ran over his knee, trapping him in the process.
A fire service spokesman said: “We had a call from the ambulance service to say there was one person trapped under a tractor. Two appliances, a heavy rescue tender and our technical rescue team attended and the man was released using airbags.”
The incident was left in the hands of the medical team.