k, appeal judges overturned his 2016 conviction on charges of war crimes and crimes against humanity.
Bemba is yet to be sentenced for the separate charge of bribing witnesses.
Judges ruled that he could join his family in Belgium, while he awaits sentencing in that case.
He had already served more than 80% of the maximum possible sentence of five years for bribing witnesses, so it would be "disproportionate" to keep him in custody, judges said.
Bemba was arrested in Belgium in 2008 after the ICC issued an international arrest warrant for him.
He was accused of failing to stop his rebel forces from killing and raping people in neighbouring Central African Republic in 2002 and 2003.
Bemba was convicted in 2016, and sentenced to 18 years in prison.
The trial was the first before the ICC to focus on sexual violence as a weapon of war.
Bemba is expected to contest presidential elections
Bemba waged a long legal battle to overturn his conviction and last week appeal judges finally ruled in his favour.
They said he could not be held criminally responsible for crimes committed by his troops.
Human rights group Amnesty International said his acquittal was a "huge blow" for the victims of a "horrifying campaign of rape and sexual violence".
ICC prosecutor Fatou Bensouda described the ruling as "regrettable and troubling".
The judges ordered what they called Bemba's "interim release" under specific conditions, including barring him from making public statements on the case, changing his address without prior notice, and contacting witnesses.
He is due to be sentenced on 4 July after being convicted in a separate case of corruptly influencing witnesses and falsifying evidence during his war crimes trial.
Bemba's release could have an impact on politics in DR Congo, where he maintains a loyal support base, reports the BBC's Anna Holligan from The Hague.
One member of his party told our correspondent that Mr Bemba now hopes to run for president in elections scheduled for December.
Who is Jean-Pierre Bemba?
Bemba had good relations with some of Africa's leaders