The deceased was identified as Mainur Rahman Nishat, 27, son of Golam Sarowar.
Civil Surgeon Dr Humayun Hasan Shanin said Nishat was taking treatment at his home after he fell sick three days ago.
Samples of the deceased were collected for coronavirus test after his death, he said.
So far, the district has confirmed 30 coronavirus cases, he added.
Meanwhile, 145 died and 5,416 were infected by COVID-19 in country until Sunday.