The female constable made the allegations after her boyfriend - also a police officer - found love bites on her breasts and neck and bombarded her with questions.
She made a formal complaint three months after the incident in which she claimed a colleague, whom she had considered a close friend, had got drunk and attacked her.
Michael Seear, 25, from Lightwater, Surrey, who has been suspended from duty for almost a year, showed no emotion as he was freed from the dock by Judge Richard Lowry after a six-day trial.
He had denied raping the 25-year-old female officer in the early hours of 1 January 1994. He accused her of making up the attack to hide their relationship from her boyfriend, who had been one of his best friends.
Mr Seear described as "complete fabrication" the woman's claim that he had drunkenly attacked and raped her after she helped him into his room at the police lodgings.
Mr Seear, with Surrey Police, said the woman had come into his room voluntarily and they had started kissing passionately. He had given her love bites. But when she said "Ouch" after one, he had stopped.
"I know that when a woman says no she means no and that is it - she means enough is enough," he told the court.
They had kissed and cuddled on the two nights immediately before the party, he said. They had been attracted to each other but decided not to pursue it as she was going out with his closest friend - who also lived in the police section house.
Mr Seear said afterwards that he was "pleased the ordeal is over. I suppose I do feel angry. I still cannot understand why the allegation was made."
Saying he had not slept properly for 10 months, Mr Seear added: "It has been a very difficult . . . I hope to get back to duty very soon. It has not put me off my career in the police at all."
His relatives in the public gallery hugged each other after the verdict.
The two officers both took other jobs to gain the necessary maturity before joining the force as probationers in 1993. She was a former nurse and he worked for a mortgage company and as a civilian worker at Scotland Yard.
Det Supt Rodger Hawkins, the senior investigating officer, said afterwards that both officers would be welcome back on active duty.
"She has been off as a result of a car accident. Both will be given every help to rebuild their lives."
Asked whether there would be any change in section house policy, he said it would be looked at "but I suspect it will not change. These are adult people, doing adult jobs, relying on each other - sometimes for their lives."
He agreed it would probably be difficult for the female officer to return to work, but said that she would be given "every encouragement".
A Surrey Police Federation spokesman said he felt sadness "over the entire incident which has been damaging for all parties involved, the police service and, in particular, Surrey Police".Reuse content