The American was arrested along with the former president of the Nissan-Renault-Mitsubishi group, Carlos Ghosn, under the accusation of removing compensation of 5 billion yen (around 39,775 million euros), as well as some tax deviations for a minimum period of 5 years.
The release was made possible after the court rejected the prosecutor's appeal, which contradicted the decision to repair the 70 million yen bail, equivalent to 550 thousand euros.
According to the current concession, Kelly can't leave Japan and his movements are limited to certain areas.
In the last days, the wife of the former man has published a video to openly request his release because of the deteriorating health condition of the husband.
Kelly, 62, actually suffered from spinal stenosis, abnormal spinal shrinkage, and must undergo surgery in the United States in early December.
Both Kelly and Ghosn have so far refused accusations during interrogation.
The former US prosecutor also issued a statement immediately after his release by his lawyer, reaffirming his innocence, willingness to return his name and return to his family as soon as possible.
Carlo Ghosn, on the other hand, will remain in prison at least until January 1, after a third official arrest warrant last Friday, on suspicion of abuse of trust in the automotive group, in connection with alleged loss of investment coverage with Nissan's funds.