Additional Chief Judicial Magistrate Ravi Kumar granted bail to Mr Kushwaha on a personal bond of Rs 10,000 soon after the minister surrendered.
However, the judge took exception to the presence of security guards and other people with the Union Minister of State for Human Resource Development when he appeared before him in court. The guards and the others were asked to leave the room.
A case was registered at Town police station at Katihar in 2009 by polling officials against Mr Kushwaha after his posters were found at the counting venue.
The case was filed under the Prevention of Defacement of Property Act.
Speaking to reporters later, Mr Kushwaha demanded a CBI probe into the allegations levelled by senior BJP leader Sushil Kumar Modi against RJD supremo Lalu Prasad and his family members.
"There must be a probe into the charges that the RJD supremo and his family members have amassed immovable property beyond their known sources of income," he said.