Voting started at 9am and will continue till 5pm.
Three candidates are contesting for the chairman post. They are Najrul Islam of Awami League, Tasikul Islam of BNP and independent candidate Ziaur Rahman.
A total of 381,914 voters of one municipality and 14 unions of the upazila are casting votes at 157 voting centres.
Motawakkil Rahman, returning officer and district election officer, said necessary steps had been taken to hold a peaceful election.
Rapid Action Battalion (Rab) members were deployed as striking force beside Ansar, Police and BGB, he added.