Helen Sarkar was granted bail on a Rs 5,000 bond, her counsel Subhas Dutta said.
Sarkar, principal of the Christ Church School in Dum Dum, was arrested on Thursday night and subsequently remanded to three days' police custody following protests by parents who blamed her for the death of 11-year-old Oindrila Das.
The Class 5 student died on Wednesday a week after she was allegedly locked up inside the school toilet by some of her seniors who demanded money from her.
Sarkar was booked under several non-bailable charges following a police complaint by the dead girl's family.
The protestors on Thursday vandalised the school and forced Sarkar to publicly apologise for Oindrila's death as well as step down from the principal's chair.
Over a dozen people have been arrested so far for the vandalism, which has evoked criticism from political parties and Governor M.K. Narayanan.