A well-dressed pervert sexually attacked a 23-year- old woman in her West Village apartment, police said.

Surveillance video shows the suspect casually sauntering down the street dressed in a gray suit and white shirt at about 2 a.m. last Thursday.

He follows the woman into her building, where, off camera, he crashed into her apartment, grabbed her from behind and sexually assaulted her.

The victim was treated at a local hospital.

The suspect is described as about 35 years old, 5-foot-7 and 180 pounds.