Police said the bus was on its way to Midnapore town from Palashchapri in the district when it hit the culvert near Panchkuri village this afternoon.
The dead included passengers and pedestrians, the police said adding the critically injured were admitted to Midnapore Medical College and Hospital.
The locals jumped to the rescue and broke windows to pull out passengers from the bus. About 20 injured were admitted to Chandrakona and Ghatal hospitals.