The chargesheet was filed in the court of chief judicial magistrate in Saran district.
"A 346 page chargesheet was filed against school principal Meena Devi and her husband Arjun Rai," police official Raj Kaushal said.
Both Meena Devi and Rai are in jail.
Kaushal, who is the investigating officer of the case, said that chargesheet was filed under various sections including 302 (murder) and 307 (attempt to murder).
The chargesheet was filed in the court of chief judicial magistrate in Saran.
"It was stated in the chargesheet that Rai purchased pesticide from a sugar factory and he kept the pesticide in the room where items for cooking mid day meal were stored. The food was cooked with pesticide," Kaushal said.
He said that adequate evidences were collected against both accused in the case during investigation.
Meena Devi was the principal of the government primary school at Gandaman village in Saran when the children died after eating contaminated food July 16. She was arrested a week after the deaths.
A first information report was registered against her on charges of murder and criminal conspiracy, police said.
Her husband Rai, accused of buying the pesticide that got mixed with the food, was on the run after the mid day meal tragedy and surrendered in court two months ago.
A forensic lab report confirmed traces of toxic insecticide were found in the cooking oil used for making food at the school, police said.