A wanted militant blew himself up in the office of a Saudi prince responsible for security, state news agency SPA has reported, BBC reported.
The man had wanted to personally tell Prince Muhammad bin Nayef in his Jeddah Interior Ministry office that he would give himself up.
The prince, who was meeting well-wishers for the holy month of Ramadan, was slightly injured.
The news agency did not identify the suicide bomber.
Saudi-owned al-Arabiya television showed Prince Mohammed meeting King Abdullah later.
He has been involved in the kingdom's anti-terror strategy.