Do Trong Hung of Bien Hoa City was arrested by the police on Wednesday.
At around 6 a.m. on April 23 he came to the school in Bien Hoa by motorbike, climbed up to the second floor where he encountered the seven-year-old girl in a hallway.
He asked her where the restroom was and took her there with him.
The police accused Hung of having sexually abused the girl inside the restroom.
Following a complaint from her parents, the police checked camera footage and identified Hung as the culprit.
Hung confessed to his crime at the police station.