The news of Babak Zanjani's arrest was announced by prosecutor general Gholam Hossein Mohseni Ejei, who did not provide any other details, the official IRNA news agency reported.
But IRNA said the case against Zanjani -- who is said to have become rich by helping Iran to circumvent global sanctions on its vital oil exports -- was related to "financial crimes".
It added that Zanjani had been taken to Tehran's notorious Evin Prison.
Zanjani oversees a conglomerate that comprises 65 companies which bring him an annual income of six to seven billion dollars, according to his website.