Judge Virender Bhat made the remarks after ruling that sex between two adults on the promise of marriage did not amount to rape.
Pre-marital sex remains a cultural taboo in India.
Last year, a court in Delhi said live-in relationships were immoral and an “infamous product of Western culture”.
Judge Bhat presides over a fast-track court set up in the Indian capital to dispose of cases relating to sexual offences against women.
He made his latest remarks while clearing a man employed with a multinational company of charges of rape.
The 29-year-old had been arrested after a woman working in a different company lodged a complaint of rape against him in 2011.
The woman alleged that the man had sex with her after promising marriage.
“In my opinion, every act of sexual intercourse between two adults on the assurance of promise of marriage does not become rape, if the assurance or promise is not fulfilled later on by the boy,” Judge Bhat was quoted as saying by the Press Trust of India.