Those dead include Mohammed Yashin (45) who was driving the car and three on tempo including its driver, sub-divisional police officer (SDPO) Mohammed Qashim said.
Yashin's wife, who was also in the car, is seriously injured, the SDPO said.
He said the couple were on way to Siliguri in West Bengal from Siwan in Bihar when the accident took place.
The injured persons have been admitted to Thakurganj Primary Health Centre for treatment.