Rajshahi Metropolitan Sessions Judge Ashraful lslam issued the order on Thursday after hearing his bail plea.
The BNP leader might be freed from the Rajshahi Central Jail in the evening, his lawyer Mozammel Haque said.
Earlier, on Tuesday, Rajshahi Metropolitan Magistrate Biswanath Mondol ordered Minu into jail, though he sought bail after surrendering to the court.
On June 4, 2011, BNP activists had attacked policemen from a procession in Bhuban Mohan Park, Rajshahi city, said Boalia Model Police Station OC Ziaur Rahman.
Former OC of the same police station Khan Mohammad Shahriar was hit by bullet in the attack, Rahman said.
Three other policemen were also injured.
SI Jahangir Alam filed a case in connection with the incident at the Boalia Police Station, accusing 350 people.
On Feb 4 this year, the police filed a charge-sheet against 133 people, including Minu.