Ranodeep, who was returning home from a show, was pilion riding on a friend's two-wheeler.
He suffered serious head injuries when the bike rammed into a concrete wall in New Alipore area at around 2 am, police said.
His friend Joydeep, who was on the driver's seat, was also injured and suffered serious fractures, police said.
Ranodeep is under treatment at a private hospital in Park Circus area, a film director, who worked with him, said.
The 35-year-old actor had been critically acclaimed for his roles in Anjan Dutta's 'Dutta Vs. Dutta' (2012), Moinak Bhowmik's 'Family Album' (2015) and Kamaleswar Mukhopadhyay's 'Khawto' (2016).