It added: "All legal steps are now being taken with regards to this decision by a court of first instance".
Robinho, who is now playing for Brazil team Atletico Mineiro, was found guilty of committing the rape with five other people.
The 33-year-old, who is now back playing football in Brazil, denied assaulting a 22-year-old woman at a Milan disco. The married forward along with five other men have been charged. Even if the former Milan player loses the appeal, he would still have to extradited to serve prison time in Italy.
Prosecutors had requested jail terms of 10 years, reported the ANSA news agency, and one of Robinho's alleged friends, Ricardo Falco, another Brazilian, was sentenced to nine years.
A statement has been issued on his Instagram profile, from his lawyers, denying he was involved.
The forward sent shockwaves through the world of football when he made a sensational £32.5million deadline day move to Manchester City in September 2008.
Camera IconRobinho failed to set the Premier League alight during his time with Manchester City.
He then went on loan to Brazilian side Santos, before joining Milan.
He's been with Atletico Mineiro since February of past year.
Robinho had previously been accused of sexual assault while at City in 2009, but was later cleared.