The four men are accused with Bemba of presenting false information and witness tampering in Bemba's war crimes and crimes against humanity trial.
Bemba, 51, faces three war crimes counts and two of crimes against humanity for murder, rape and pillage committed by some 1,500 members of his private army in the neighbouring Central African Republic between October 2002 and March 2003.
"Today Judge Cuno Tarfusser ordered the release of Aime Musamba Kilolo, Jean-Jacques Mangenda Kabongo, Fidele Babala Wandu and Narcisse Arido," the Hague-based ICC said in a statement.
Kilolu is Bemba's defence lawyer and Mangenda his case manager in the war crimes trial, while Wandu is a Congolese parliamentarian and member of Bemba's Congolese Liberation Movement (MLC).
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The three were arrested in November and December last year.
Arido, a defence witness, was transferred into the ICC's custody in March.
Although freed, the four men could still be found guilty on the charges, the ICC said.
"In the event of conviction, the court may impose a term of imprisonment not exceeding five years, or a fine, or both," it said, adding "the suspects shall appear before the court when requested".