A Paris court ruled that Mr Kerviel was free to go while investigations into the scandal continued.
SocGen admitted in January that it had been the victim of record-breaking losses, for which it blamed Mr Kerviel for taking unauthorized positions.
Mr Kerviel has been imprisoned for the past five weeks while allegations of breach of trust, computer abuse and falsification were investigated.
The disgraced trader told the court that colleagues at the bank were aware of his actions and even helped him, while SocGen claims that he hid his actions from it.
But Mr Kerviel has been successful in his bail application, which is not good news for SocGen.
The 31-year-old is expected to leave Paris' La Sante Prison later today.