Shyam, Atul, Ankur and Rajpal were arrested along with a juvenile from near Rithala on Friday, police said.
Two country made pistols, three live cartridges, a stolen motorcycle, a Maruti van and Rs 3.36 lakh were recovered form their possession.
They were arrested from near Rithala Metro police station on Friday acting on a tip-off that they would come there.
On frisking, a country-made pistol and two live cartridges were recovered from their possession.
On sustained interrogation, they disclosed that in recent past they had robbed Rs 10.50 lakh from a person going in a vehicle near G D Goenka School in Rohini.
"They also disclosed that a juvenile was also involved in both the cases. On their instance, the juvenile was also apprehended from his house," a senior police offical said.