According to a complaint lodged by the victim's mother, she would leave for work and the accused would be alone in the house with the girl when he would rape her, SHO Arun Kumar Tyagi said.
He had been raping his daughter since January. The incident came to light when she become pregnant and she informed her mother about it, he said.
The accused had threatened to kill her if she disclosed the matter to anyone, Tyagi said.
The accused was arrested and he confessed to his crime during interrogation, the SHO said.
The victim has been sent for medical examination.