The officer involved in metro security said that the incident occurred in this morning at the Adarsh Nagar metro station when a CISF personnel detected bullet-like objects in a bag being screened at the X-ray machine.
The bag belonged to a man identified as 21-year-old Shahbaz, a resident of Muzaffarnagar in Uttar Pradesh.
During search, three bullets of .315 calibre were recovered from the bag, the officer said.
The man was handed over to police after he failed to furnish any government-issued document for possessing arms and ammunition, he said.
Carrying arms and ammunition in the Delhi metro is banned under the law.
This is the second case since Sunday, when an 18-year-old man from Bareilly was apprehended at the Kailash colony metro station of the Delhi Metro for carrying three live bullets in his bag.