The factory housed in a secret location in Miranshah was found during a house-to-house search by infantry and commandos.
Huge quantity of material used for making bombs and suicide vehicles were found in the complex, the military said in a statement.
The material recovered includes 10 anti-tank mines, 225 explosive filled cylinders, 150 empty cylinders, 400 prepared pellets filled with nuts and bolts, 700 prepared pipes filled with explosives, training manual and equipments used for making bombs.
The latest discovery shows that the region was a hub of militants who used the factory for launching attacks in the country.
Pakistan launched a massive operation on June 15 to clear the tribal belt of foreign fighters and Taliban militants. So far more than 370 militants have been killed.
