An Interior Ministry statement, on the official Saudi Press Agency, said the terrorist suspect was arrested after shooting three policemen on Tuesday at a checkpoint in the ultra-conservative northern Qassim province, site of several shootouts with al-Qaida-linked fighters.
Muhammad Abd al-Rahman al-Suwailmi died from his wounds later on Tuesday, an Interior Ministry spokesman announced early on Wednesday.
Earlier, the same insurgent had killed two policemen on patrol near the northern town of Buraida.
Saudi-owned Al Arabiya television said al-Suwailmi was on a list of 36 wanted insurgents linked to al-Qaida.
It said al-Suwailmi was an internet specialist who had helped the Saudi wing of al-Qaida post statements on the web.
The Interior Ministry statement said he had been wounded during his arrest.
"He is considered as one of the terrorist leaders," said a source. It was not clear if the man was alone in the vehicle or had accomplices.
Saudi Arabia, birthplace of Osama bin Laden, has been battling a two-year wave of bombings and shootings by supporters of al-Qaida.
The last major attacks took place nearly a year ago and security forces have since killed several leading insurgents in clashes.
According to the latest official figures, at least 90 civilians, 49 security personnel and 118 insurgents have died since the unrest began. Hundreds more have been wounded.