TOKYO — Jack Benny, perennial 39-year-old comedian who will celebrate his 49th year in show business in a few months, was lounging in a dressing gown at his Imperial Hotel suite Tuesday morning after a spur-of-the-moment decision brought him vacationing to Tokyo.

He and wife, Mary Livingstone — now retired and known simply as "Mrs. Benny"— made their whirlwind plans to fly here after their good friends, the Mervyn LeRoys, idly told of their intended trip.

"Mary had never been and I haven't been back since 1951 when I took a troupe to Korea, so we made arrangements in a couple of days and here we are," Benny told Stars and Stripes.

The apparent discrepancy between his famed claim to remaining in his pre-forties and the fact that he will have a half-century in the theater next year has never fazed two generations of Americans who have alternately smiled, chuckled and roared at Benny and his entourage on radio and television.

After reaching the 50-year milestone, are there any plans for retirement?

"None at all," bespectacled Benny insists. "I've got to work. I like it.

"In fact, beginning next season, my television show goes on weekly instead of our current twice a month schedule, including some live telecasting."

Adding more work to this hectic, deadline-crammed agenda is a series of serious violin concerts which Benny plays with well-known symphony orchestras.

"I have a May 8 concert with the Denver Symphony — and I'm behind in my daily practice. I've got to find a violin to use while I'm in Tokyo," he said.

He played a concert with the Honolulu Symphony three weeks ago on his way to the Orient. Receipts from his concerts go to the symphonies themselves for musicians' retirement funds. The Honolulu concert netted $25,000 at .$100 a seat and pulled the orchestra out of a financial hole.

The violin was the vehicle for Benny's entrance into show business when he was 17. He met Mary Livingstone in Vancouver, B.C., when she was 13 and he was traveling in a show with the Four Marx Brothers. She and Gracie Allen retired together last year.

Asked about the current crop of "sick" comics, Benny replied:

"The very fact that they are called 'sick' Indicates they won't last. Anyone who relies on taking potshots at religion, illness, the mentally retarded to get laughs will never make it in show business. It's too sincere an art."

"Jack has never delivered a vicious line in his life — and he's been on radio since May, 1932," Mrs. Benny interjected.

His radio show was discontinued two years ago and Benny now concentrates on television.

"New comedians? Joey Bishop is the funniest man I've heard in years," Benny said. "I actually, physically fall down laughing when I hear this guy. I can't stand up. I scream. A lot of comedians amuse me and I understand what they are doing to get laughs, but I don't yell myself. Bishop breaks me up.

"Alan King is good, and I like Shelly Berman a lot among the newcomers. Mort Sahl is also great. I only wish he liked me as much as I enjoy him. He thinks I stink. Makes jokes about me. I think he's funny."

Benny suddenly jumped to his feet and acted out a bit of business from his May 1 television show — involving his sponsor and his option. It was hard to see how anyone could think Jack Benny isn't funny.