The incident, which occurred on Friday last, came to light when the child complained to her parents. She told her parents that the man, who is a supervisor at her school, misbehaved by touching her private parts, they said.
After consulting doctors who suspected a sexual assault on her, the minor's parents lodged a complaint with police.
Police said they registered a case on Saturday under provisions of the Protection of Children from Sexual Offences Act (POCSO) and IPC, and arrested the accused.
Based on the complaints from parents, police took the Principal of the school into custody for questioning.
Parents have alleged that the Principal did not initiate action against the accused and tried to defend him.
They also claimed that CCTV footage would not be available as the accused was in-charge of CCTV operations at the school.