Ecclestone was taken to a facility in Viracopos airport in Campinas, Sao Paulo following his arrest but released after paying bail
In a statement on Thursday, local police said they found an undocumented LW Seecamp .32 gun in the 91-year-old's luggage during an X-ray screening.
Ecclestone acknowledged owning the gun, but said he was unaware it was in his luggage at the time.
After paying bail Ecclestone was freed to continue his journey to Switzerland.
Ecclestone, who spent 40 years as the head of Formula 1 before stepping down in 2017, is married to Brazilian-born Fabiana Ecclestone.
Speaking to the Press Association on Friday, Ecclestone said he had not been arrested and had instead been "questioned" because the gun was not registered and spent a "few hours" with police.
He paid 6,000 Brazilian reals (£998) and the gun was confiscated.
Ecclestone said the gun was not loaded and had been packed in his luggage by accident.
-- Courtesy of BBC Sport