The most exclusive hair salon in the country, the one-chair barbershop in the White House basement where the President has his hair cut, became a one-day-a-week unisex hair facility yesterday.

And as opening days go, business boomed.

Every appointment in the noon-to-6 schedule was taken, two of them by men - and there was even some advance bookings - according to Belgain-born Yves Graux. Graux and his wife, Nancy, owners of Hair of Capitol Hill, are staffing the shop.

"Almost before we got the notice out, the appointments were filled, so the usher's office just stopped taking them," said Margaret Mckenna, No. 2 in the Office of the Counsel to the President and first-in-line for a styling.

The small underground shop, with its blue-and-white wallpaper, one shampoo bowl and single blue-and-white barber chair, was once the hair cut hangout for Richard Nixon, Gerald Ford, Henry Kissinger and Alexander Haig. Jimmy Carter retreats there every third week or so, ordering barber Rodriguez Morales to "cut it short." Susan Clough, the Prisident's secretary, or Tim Kraft, his special assistant for appointments, usually call ahead to tell Morales to cut short the scissoring and leave Carter's hair long.

The second and third appointments yesterday were June Frazier of the White House Vistors' Office and Wilma Sands, assistant to White House curator Clem Conger.

Sands sat under the dryer in one corner Fraziersat in another as Nancy Graux administered the hand held blow-dryer. On center and in the barber chair undergoing same final touches at the hand of Yves Gruax was Margaret McKenna. Her long blonde hair swept back "just the way I want mine to." pleaded an under fied woman who had opened the door to see if there had been a last minutes cancellation.

"Sorry" said Yves Graux who had moved in that morning with little of no fanfare lie squeezed a couple of extra chairs the hair dryer and a tray of hair collers into the basement cubicle.

For semi time McKenna has wondered why there was a barbershop for men at the White House but no hair salon for women.

"Everyone works long hours," she said.

Tim Kraft who had recruited Morales to cut Jimmy Carter's hair last winter told McKenna he knew of no procedural officulties. The arrangement would be informal and without contract.

"An open administration, an open barbershop," Kraft said.

Yves and Nancy Graux, who bought their Capitol Hill shop a year and a half ago have as regular clients Dr. Peter [WORDS ILLEGIBLE] Press Secretary Jody Powell and McKenna so there wasn't much of a problem choosing the [WORD ILLEGIBLE]

After a positive response to an informal survey of women McKanna sent sat a memorandum on Nov. 22 announching that Graux would be at the White House on Friday Dec, 1 for 5 hours Feer for a shampoo styling and blow dry would be $10 for men and $12 to $18 for women depending upon length of hair.

The two men [WORD ILLEGIBLE] yesterday's appointments book were regarded as a good sign that there was no discrimination felt by male co-workers according to McKenna. "We're not trying to encourage men to come." she said. "They've got a barber."

Across town, Paerto Rico-born [WORD ILLEGIBLE] Moraies said the unisex shop did not concern him because he never had specialized in women's hair styling.

"I'm just a plain barber," he said.

And since two men were among the opening day's appointments was he worried that his White House business might suffer?

"I feel very proud that I go down and cut the President's hair. It's an honor. And I don't feel jealous of any one. I'm the coolest guy when it comes to that.