Sharma was admitted to the Deen Dayal Upadhyay Hospital after he consumed pills and tried to hang himself on Wednesday night.
He was hospitalised in the at 12.02 a.m, a hospital official said.
Sharma's lawyer A.P. Singh claimed that it was not a suicide attempt but attempt to murder.
"Few days ago, I met him in jail where he complained about torture inside the jail premises," Singh told IANS.
Sharma, Mukesh, Pawan, Akshay Thakur and Ram Singh, along with a juvenile, were accused of gang-raping and assaulting a 23-year-old paramedical student inside a private bus. The victim and her friend were thrown out of the bus after the crime.
The victim died of grave intestinal injuries December 29, 2012 at Singapore's Mount Elizabeth Hospital where she was airlifted for specialised treatment.
In 2013, Ram Singh was found dead in the Tihar Jail.
