A balding and bespectacled 55-year-old former federal employe went on trial yesterday in Montgomery County Circuit Court on four counts of child pornography, the first such case in the county in at least 10 years, according to the deputy state's attorney.

Laszlo Emil Szeguary, of Rockville, has been charged with soliciting, inducing and permitting a boy and a girl under 12 years old to engage in sexual contact while being filmed at his Rockville home in June 1984.

If convicted, Szeguary, who formerly worked for the U.S. Bureau of Standards, according to his lawyer, faces a maximum of 10 years in prison and a $15,000 fine or both.

Deputy State's Attorney Louis Lear said this was the first child pornography case in his 10 years with the county prosecutor's office.

After opening arguments before Judge William M. Cave, a 14-minute video tape was introduced into evidence showing two children having sexual contact on the floor of what was identified as Szeguary's living room.

Four children yesterday gave varying versions of the alleged incident.

One 12-year-old boy, who was 11 at the time, testified under cross-examination that five children went to the defendant's home to see a film of Szeguary taking a shower that some children had secretly watched through the window of Szeguary's home a few days earlier.

The boy said Szeguary refused to show it. He said the girls asked Szeguary to film the children in the house.

The boy said the children were willing participants and that the girls asked the boys to take off their clothes.

The same boy admitted under cross-examination that he lied in a statement when he told police that the filming was Szeguary's idea.

The boy testified that the girls urged the boys to take off their clothes.

However, one girl who testified yesterday denied asking the boys to take off their clothes. She said Szeguary started filming them with clothes and then told the children, "We had to do more stuff than have our clothes on."

Defense attorney Thomas L. Heeney said yesterday that the activity on the tape was not legally obscene. The children in this case are setting Szeguary up, he said.

Szeguary did not request a jury trial because, Heeney said, he preferred having Cave decide the case.

"The judge can more appropriately, without prejudice and without bias, understand and consider the evidence," Heeney said.