Acting on a complaint by International Justice Mission, an NGO, district officials conducted a raid on the unit and rescued them, they said.
The children were aged between seven to 12 years, they said.
The owner of the unit were paying between Rs eight to 32 per person a week, which was below the Tamil Nadu Minimum Wage Act of Rs 136.02 per day, they said.
The owner also denied them the freedom of movement and permision to work outside of the facility, they said.
The rescued were issued release certificates by Sub Collector of Kancheepuram Revenue Division K Sakthimani.
Bonded labour is a severe human rights violation abolished by the Bonded Labour Abolition Act, 1976.
