The development in the case was reported by the BBC, which said bail was set at $4.5 million.
The British broadcaster quoted the Swiss justice ministry as saying it would decide quickly whether to challenge the court's decision to release Polanski on bail.
Polanski, 76, was arrested Sept. 26 in Zurich in connection with a 1977 child-sex case in Los Angeles.
The famous auteur, who lives in France but was in Switzerland to attend a film festival, has not traveled to the United States since he pleaded guilty in a Los Angeles court to having unlawful sex with a minor and then fled the country before he could be sentenced. He was accused of drugging and having sex with a 13-year-old girl.
Polanski's lawyers have alleged misconduct on the part of the Los Angeles criminal justice system at the time of the plea deal, and are fighting extradition from Switzerland to the United States.