Hundreds of HT activists, who drove to Rajshahi from the capital as news on their getting bail came through, greeted them as they came out of the Jail gate at 8pm.
The release came as they posted bail from the Rajshahi District and Sessions Judge's Court earlier in the day.
The Hizb ut-Tahrir high-ups were detained at Rajshahi City Press Club on September 18, before a scheduled press conference there.
Invoking Section 54 of the Criminal Procedure Code (CrPC), police showed them arrested on suspicion of using religious sentiments to foment anti-government activities and having involvement in militancy.
A metropolitan magistrate court later in the day rejected their bail petitions as police said investigation into the allegations were still going on.
The accused appealed to the district and sessions judge's court after the lower court again rejected their bail petitions the following day.
They posted bail yesterday in the morning and were freed after paperwork reached jail authorities in the evening.