The accused identified as Arjun Singh, who was an acquaintance of the minor victim's family, was arrested and sent to jail today, sources said.
The minor girl, who was living with her paternal uncle and aunt, was alone at her home yesterday when the accused allegedly lured her and raped her.
The victim was studying in a school in the industrial township of Adityapur, police said.
The accused was arrested today after a FIR was registered under relevant sections of ST/SC Atrocities Act, the POCSO Act and section 376 of the IPC, they said, adding that the girl was sent for medical examination.