A creep showed three young girls a homemade pornographic video as they rode a subway through upper Manhattan, police said Thursday.

The stranger was sitting across from two 13-year-olds and a 12-year-old as they rode a northbound C train approaching the 163rd Street-Amsterdam Avenue station shortly before 5 p.m. Wednesday, cops said.

Without saying a word, he displayed to them his cellphone, which had a self-made, sexually explicit video playing, police said.

One of the teens snapped a photo of the pervert — who was wearing headphones, a rainbow baseball cap and a white shirt with a flower and Asian characters and holding his cellphone in his right hand — before the girls left the train.

The suspect is still on the loose.