The incident took place on Thursday when the accused constable, Subhash Singh, entered the minor's house in the absence of her mother and allegedly raped her.
Hearing the screams of the child, the neighbours came to her rescue and beat up the constable.
He was then handed over to the police.
A case has been registered against the accused under the Protection of Children against Sexual Offences (POCSO) Act.
The child has been sent to the district hospital in Noida for medical examination. (ANI)