Barry Paul Lebowitz, whose pose as a wealthy businessman and bon vivant ended when he was arrested and described by authorities as a "con man" was convicted by a U.S. District Court jury yesterday of fraud charges for bilking his admirers out of more than $13,000.

Lebowitz, 43, a one-time clothing salesman from Skokie, Ill., who fancied expensive clothes and fine hotels and who asserted that he owned a penthouse and worked for a leading supplier of casino gambling equipment, stood attentively with his hands folded in front of him as the jury verdict was announced. Judge Louis F. Oberdorfer scheduled sentencing for Aug. 13.

The prosecution had charged that Lebowitz used his considerable charm and pretentions of success to persuade women he met, and their friends, to give him money, most of it, he said, to invest in stock with Bally Manufacturing Corp., for whom he said -- falsely -- that he worked. Other times, it was said, he simply portrayed himself as good for a loan that he promised to repay, but didn't, according to testimony.

In the end, Assistant U.S. Attorney Timothy J. Reardon III told the jury, Lebowitz was "captured by the very tool with which he made his mini-fortunes -- his mouth."

One of his victims, Pauline Evans, A Vienna businesswoman, secretly tape-recorded their conversations in February 1980, after Lebowitz got $1,300 from her. The tapes were played for the jury during the trial.

"I want an explanation. I think I deserve an explanation," Evans said during one conversation. Lebowitz replied, "It's all lies," according to the tape played in court.

"What do you mean by that? You didn't love me?" Evans said later. "Of course I love you," Lebowitz said. "Well then, what was lies?" she asked. "Everything else I told you. Except that," he said.

"Then who are you? Is your name Barry?" she asked, and he said yes. "And where are you from and what do you do?" she asked. "I'm a con man," he said in the tape.

"Who is Barry Lebowitz?" Reardon asked. He moved in on women, meeting them from such places as the bar at the Four Seasons to the revolving doors at Bloomingdale's, Reardon said, taking money from them. He would make deals with men he met through the women, Reardon said. If things got "hot," Reardon said, Lebowitz would "pick a fight with the woman" and disappear.

Admittedly, Reardon said, the jurors could say of the victims that "these people must be in a daze; what are they doing" giving Lebowitz money without asking questions. "Well, they're people, they make mistakes," Reardon said.

Lebowitz's court-appointed lawyer, R. Stan Mortenson, whose best known client is former president Richard M. Nixon, argued that what the government refused to accept in the case was "that sometimes people want to help people out." No witnesses testified for the defense and Lebowitz did not take the stand.

Mortenson said the government's evidence did not show that Lebowitz's statements about his employment and his stock deals were "absolutely false."

After about five hours of deliberation, the jury convicted Lebowitz of all 10 counts of false pretenses and one count of causing a person to travel across state lines as part of a fraud scheme.

Lebowitz is being held in a suburban Maryland jail on a $25,000 bond.