Tsotne Gamsakhurdia was arrested at Tbilisi Airport on September 3 and charged with spying for Russia, an attempted coup, and grievous bodily harm.
He had earlier been on hunger strike in protest against his arrest.
The decision was taken by the Tbilisi court of appeal on October 18 and bail of around $14,000 was paid by his mother, Manana Gamsakhurdia-Archvadze.
"If the investigation is conducted objectively, the criminal proceedings against Tsotne Gamsakhurdia should be halted due to a lack of evidence," his lawyer said.
The allegations are based on audio and video recordings made during meetings between Gamsakhurdia and Russian diplomats who were later expelled from Georgia. Gamsakhurdia claims the meetings were related to the transfer and subsequent reburial of his father's remains from the Russian Republic of Chechnya to Georgia last year.
The prosecutors also have a taped telephone conversation made in November 2007 between a Georgian opposition leader and Gamsakhurdia, where he called for a coup during the mass public protests that took place against Georgian President Mikheil Saakashvili that month.
If found guilty of the charges, Gamsakhurdia could face up to 20 years behind bars.
