The IRNA news agency quoted Behrouz Kamalvandi, a spokesman for Iran's atomic agency, as saying that Yukiya Amano "visited workshops and nearby construction sites in the complex."
The International Atomic Energy Agency has long sought greater access to Parchin, where Iran is alleged to have carried out tests in the past related to the development of nuclear weapons. Iran allowed IAEA inspectors to visit twice in 2005.
Iran denies ever seeking atomic weapons, and says Parchin is a conventional military site.