The elite Rapid Action Battalion (RAB) force uncovered the arms cache in Rajshahi city, 300km northwest of the capital Dhaka, on Friday.
A spokesman for the RAB said on Saturday: "Two hundred bombs, 2000 detonators, 144 pieces of power gel explosives and bomb-making materials were seized from two hideouts late on Friday."
The hideouts were raided after police had detained four fighters hours earlier.
On Wednesday, the RAB arrested three leading fighters, including Ataur Rahman Sunny, an "operations commander", and seized 120kg of explosives, 27 grenades, dozens of detonators and 24 revolvers in Dhaka and southeastern Chittagong.
Police said Abu Isha, one of the four detained in Rajshahi on Friday, was a regional operations commander.
Banned group blamed
Bangladesh authorities blamed the banned Jamaat-ul-Mujahideen group for a recent wave of bombings that has killed at least 30 people and wounded 150 since 17 August.
Most of those killed by bombs have been judges, lawyers, police and journalists.
"Two hundred bombs, 2000 detonators, 144 pieces of power gel explosives and bomb-making materials were seized from two hideouts late on Friday"
Rapid Action Battalion
Police have detained more than 800 suspected militants in the last four months, mostly members of Jamaat-ul-Mujahideen.
The others were activists of another outlawed Islamist group,
Jagrata Muslim Janata Bangladesh.
Bangladesh is the world's third-largest Muslim country after Indonesia and Pakistan.