An 18-year-old man convicted of raping a 14-year-old girl at knifepoint three years ago will be released early from a Howard County jail on Dec. 15, despite pleas from the victim's parents that the rapist is still a danger to society and had not acknowledged his crime.

The victim's parents had been granted an unusual rehearing of the decision by Howard County Circuit Judge Robert F. Fischer, who decided last month to release Patrick S. McIntyre from the county jail. The angry parents learned of his November ruling on television news, which reported that McIntyre planned to enroll at Howard Community College, which the now 17-year-old girl was also planning to attend.

Yesterday, Fischer refused to change his original order, under which McIntyre will be released from the county jail in Jessup nearly a year earlier than expected under parole guidelines. McIntyre, who has been in jail for 38 months, was sentenced to a six-year term by Fischer in 1985.

McIntyre's jail sentence was reduced by 19 months for good behavior. He completed requirements for a high school equivalency diploma while in jail, authorities said.

The judge, while denying the parent's request, said he would add strict guidelines for McIntyre's release: imposing a curfew, banning the young man from contacting the victim or former friends, and prohibiting McIntyre from obtaining a driver's license.

Fischer admitted yesterday he had made a mistake last month in allowing McIntyre to enroll in January at Howard Community College. "That was a bad idea," he said.

McIntyre's attorney, Alan Fishbein, said his client had decided not to enroll at the two-year school in Columbia, and instead plans to attend Essex Community College in Baltimore County, near the home of his grandparents. McIntyre must live with his grandparents in Lutherville as part of the early release order.

On Nov. 5, Fischer granted McIntyre a reduced sentence, citing the young man's age and his need for psychological counseling. Fischer placed McIntyre on five years' probation and ordered him to undergo treatment at the Sexual Disorder Clinic at Johns Hopkins Hospital in Baltimore, which administers drugs to treat sex offenders.

If McIntyre violates the terms of his probation, including failing to be admitted to the Johns Hopkins sex offender program, Fischer said he would send him to the state prison to serve the rest of his sentence.

The victim's father said yesterday that the judge's granting McIntyre early release "showed no sensitivity" to his daughter, who was severely traumatized by the rape. The girl, a senior at Hammond High School, was not in the courtroom yesterday.

McIntyre, then 15 years old, was tried as an adult and convicted in October 1985 of raping the girl, then 14, at knifepoint on the night of Sept. 14, 1984. The rape occurred as the girl was walking home on a gravel road near her home in Columbia.

The Patuxent Institution in Jessup refused to accept McIntyre in its program for prisoners with psychological disorders because he refused to admit he had emotional problems, officials said.

McIntyre was also charged as a juvenile in 1982 with raping a 6-year-old Columbia girl. McIntyre's refusal to accept responsibility for his crimes, the victim's father told Judge Fischer yesterday, was the family's main objection to his early release.

"He's being rewarded for not cooperating," said the victim's father, who said McIntyre's refusal to participate in the Patuxent program is prompting his early release. "He had a chance to cooperate and he didn't."

"If he can be required to participate in the program at Johns Hopkins as a condition of his release to attend college classes, why could he not be required to cooperate with the program at Patuxent . . . where college courses are offered?" the victim's father said, reading from a four-page statement.

As a condition for treatment at the John Hopkins Sexual Disorder Clinic, a patient must admit to having sexual and emotional problems, said Howard Assistant State's Attorney Kate O'Donnell.

Speaking in a slow, deliberate voice, the victim's father asked Fischer to place McIntyre in an inpatient residential treatment program for sexual offenders.

But Fischer said there is no public funding for such facilities. "How will we get the funding for a residential treatment center?" he asked. Fischer said he empathized with the victim and her family, but felt McIntyre deserved more than being "warehoused" at the county jail.

McIntyre's grandfather, Edward Brannock, a retired engineer, told the court yesterday that he and his wife were willing to devote "full-time" attention to their grandson.

"If given a chance, I think Patrick will be a welcome asset to society," Brannock said. "And he won't get that chance sitting in the Howard County Detention Center."