On Friday, Judge Khanna said the attack
"shocked the collective conscience" of India, and that "courts cannot
turn a blind eye" to such crimes.
"This case definitely falls in the rarest of rare categories and warrants the exemplary punishment of death," he added.
The men were convicted to death by hanging, and one of them, Vinay Sharma, broke down in tears as the verdict was announced.
The father of the victim, who cannot be named for legal reasons, said the family was satisfied with the ruling.
"We are very happy. Justice has been delivered," he said in the courtroom, according to the Associated Press news agency.
Earlier, protesters outside the court had demanded that the four men should be hanged.
As they were escorted to the courtroom, the four men shouted to the crowd: "Brothers, save us!"