The arrestees were identified as Mahidul Islam, 40, Mazharul Islam, 25, Tariqul Islam, 25 and Muzahidul Islam, 26.
Officer-in-Charge of Savar Model Police Station Saiful Islam said a female worker, a resident of Muktimor in Savar, was gang-raped by six people on Tuesday night.
Later, the victim filed a case at Savar Model Police Station that night. Police arrested Mahidul, Mazharul and Tariqul in this connection while the others remain absconding.
Besides, a young girl was reportedly raped by a man at Zadur Char area on Wednesday. Police Arrested Muzahidul after the victim filed a written complaint against him.
Meanwhile, a five-year-old girl was raped at Anandapur in the morning.
The victims were taken to the One-Stop crisis centre of Dhaka Medical College Hospital.