He was admitted to SSKM Hospital on November 20 after a brief stay at a private clinic in the city.
Mitra was summoned by CBI in the multi crore rupees Saradha ponzi scheme scam.
"The minister is keeping well now. We don't need to keep him in the hospital. The Medical Board has thus decided to discharge him," the SSKM Hospital authorities said.
"However, condition of his health needs to be reviewed from time to time," they said.
"I am in no way involved in the Saradha scam," he had said earlier.