Last week, Egyptian authorities asked Interpol to arrest the three Israelis who it said had recruited Attar.
Spying abroad
Egyptian prosecutors say Attar had previously confessed that Israeli agents had helped him to obtain a residency permit in Canada under a false name and found him a job in a bank.
They said Attar, who was arrested at Cairo airport in January, was paid $56,000 to spy on Egyptians and other Arabs during stays in Canada and Turkey and tried to obtain information on Egyptian Coptic Christians abroad.
He was also expected to approach potential recruits. Israel has dismissed the charges as baseless.
Attar arrived at the court house under heavy security and stood inside the defendants' pen.
Dressed in a white T-shirt and trousers, he made a victory sign several times to reporters and television cameras.
Media allegations
The Egyptian media has hailed Attar's arrest as a triumph for the country's intelligence services, and published details of his alleged confessions and portrayed him as a spy who had betrayed his country and religion.
"El-Attar relates the details of his downfall," the state-owned al-Ahram daily newspaper said on Saturday, describing his acts as "shameful".
The purported confessions quote Attar as saying he had converted to Christianity and was homosexual.
In 1996, Egypt sentenced Azzam Azzam, an Israeli Arab textile worker, to 15 years in jail for spying for Israel.
Egyptian authorities said Azzam passed messages in women's underwear using invisible ink.
Both Azzam and Israel had denied the charges.
He was released after eight years as part of a deal that included the release of six Egyptian students in Israel.