When first-time visitors come to the Fairfax County Courthouse, they often end up at Claire Pritchett's parking-ticket window, desperately seeking help in finding their way around in the crowded and confusing 182-year-old building.

"I think I give out more information on directions around this place than the money I collect on parking tickets," said Pritchett, who runs the county's parking ticket office from a room erroneously called the magistrate's office on the directory in the courthouse lobby.

Soon citizens won't have to badger Pritchett for directions or rely on the out-of-date lobby directory to find their way around Fairfax Circuit and General District Courts.

Just a block away from the courthouse, at Rte. 236 and Chain Bridge Road in Fairfax City, construction crews are finishing work on the county's new judicial center--a modern, $18.7 million building with spacious, well-lighted lobbies, directions to all offices and some of the most elaborate security and computer technology around. The County Circuit Court, General District Court and most of the courthouse staff are scheduled to move in this summer. The Juvenile and Domestic Relations Court will remain in the old courthouse, which is to be renovated after the judicial center is opened.

"We're real excited about the new building," said Barnard F. Jennings, chief judge of Fairfax County Circuit Court. "To some extent it is austere," he said, "but it will be far more functional than this building."

County officials say the new building is a world apart from the old courthouse, which judges, lawyers and jurors have long criticized for its cramped facilities, poor security and confusing catacomb of offices. The building's layout was complicated by the addition of several wings to the old courthouse, part of which dates back to 1800.

Few of those shortcomings could be seen in the new judicial center last week, however, when a group of visitors toured the facility as workmen put the final touches on the L-shaped, five-story building.

The center has enclosed, secured passageways directly linked to the Adult Detention Center, to enable sheriff's deputies to transfer prisoners more safely.

The building also contains a law library three times the size of the one in the old courthouse and vastly expanded file and land-records facilities that will be wired to the court's computerized file system.

Virtually every office in the judicial center is identified on a directory in the main lobby, where there also will be an information booth. What's more, courtrooms have been acoustically designed so that jurors and spectators can hear bench proceedings from the back of the room.

Financed by an $18.7 million bond referendum approved by county voters in 1977, the judicial center is designed so that more courtrooms can be added as needed. CAPTION: Picture 1, L-shaped and five stories high, the judicial center for Fairfax County, here viewed from the Massey Building, cost the county $18.7 million.; Picture 2, Workers put finishing touches on the new judicial center's lobby. Photos by CHARLES K. CROCKETT for The Washington Post