Bijoy Sagar Mishra (42) received a bullet wound on his right leg while disembarking from a crowded Howrah-Burdwan local train at around 3.30 PM at Rishra, an industrial town about 24 km from Kolkata, they said.
Mishra's bodyguards were not present at the time and the councillor rushed to the nearby police station for cover.
The assailants are yet to be traced, police said.
In a police complaint, Mishra said he had spoken out against the construction of an illegal club building in his ward and suspected that members of the club had employed goons to attack him.