Last Sunday the gondola on a cable way connecting the town of Stresa, on Lake Maggiore, to the nearby Mottarone mountain plunged to the ground, killing all aboard apart from a five-year-old Israeli boy who remains in hospital.
Italian prosecutors have opened an investigation into suspected involuntary manslaughter and negligence.
On Wednesday police arrested the three men.
According to the daily La Stampa website, the judge on Saturday ruled there were no grounds for keeping the three men in jail since they could not run away and there was no risk of evidence being tampered with.