Police found the insurgent's car packed with explosives and weapons on Monday.
The Interior Ministry said in a statement carried by the official SPA news agency that the man belonged to the "deviant group", the term used by Saudi authorities to describe al-Qaida.
The firefight on Monday was the latest such incident in the oil-rich kingdom where insurgents have been targeted by the government since a wave of attacks started in May 2003.
The suspect had refused to show police his identification after leaving his car, then "opened fire in the direction of security force members and tried to flee in another car", a ministry official said.
"There was an exchange of fire with him and he was wounded," the official said.
Security forces found powerful explosives, grenades and other weapons including Kalashnikov assault rifles, ammunition and about 20,000 Saudi riyals ($5000).
Previously an Interior Ministry spokesman had said two suspects were hit in the gunfight without disclosing their condition, while Al-Watan newspaper reported that one had managed to escape.
A security source had earlier said two members of the security forces were wounded in the firefight late on Monday.
Saudi Arabia has been battling anti-government fighters loyal to Osama bin Laden's al-Qaida network, who have staged several bloody attacks on foreign residents, government sites and energy-related installations in the past two years.