The arrested were identified as Mithun (20), Nizam (32), Ali Akbar (31) and Yusuf Sulaiman (28), they said.
Police said Mithun, who knows the 14-year-old girl, took her in his motorbike after the school hours and dropped at a bus stop on Thursday.
Nizam, who saw the girl at the bus stop, took her in his bike and met Akbar and Sulaiman. They took the girl in a car and roamed around and sexually assaulted her in the vehicle. Later they dropped the girl at a bus stop.
People in the bus stop who grew suspicious questioned the girl and informed her relatives.
When the girl told the relatives about the incident, they registered a police complaint. The four were arrested today, police said.