The accused, Irfan Salim Khan, a resident of Bandra, was arrested last night after the parents of the child filed a complaint against him at Nirmal Nagar police station, a police official said.
The accused had lured the seven-year-old victim, who is his neighbour, to accompany him to his house last month by offering chocolates, where he forced the child to indulge in "unnatural sexual acts," the official said.
Khan had threatened the boy with dire consequences if he revealed anything to his parents, he said.
After the victim informed his parents, the matter was brought to the notice of Nirmal Nagar police yesterday which arrested the accused last night.
A case has been registered against Khan under relevant sections of the Protection of Children from Sexual Offences (POCSO) Act, 2012, the official said.