The accused -- Sachin Londhe -- was arrested from his residence at Mhada Colony in central Mumbai, DCP (Detection) Dhananjay Kulkarni said.
The 15-year-old girl, who was repeatedly raped by Londhe, is pregnant, he added.
"An FIR was lodged yesterday at the Wadala TT police station and the accused was arrested today," Kulkarni said.
The girl, who is a school student, knew the accused from childhood, the police official said, adding that Londhe and the girl stayed in the same colony.
Londhe had allegedly raped the girl on several occasions in the past, the police official said.