"He wants to help the indigenous population here and wants to know how to channel the funds," President Oscar Arias told reporters outside his home, where he met with Gibson for about an hour.
Arias said Gibson — who starred in such Hollywood blockbusters as the "Lethal Weapon" series and directed last year's Mayan epic "Apocalypto" — would return to Costa Rica in a month to arrange how much money he would donate and to which organization.
Gibson has avoided the press in prior trips to Costa Rica, but spent a few minutes answering questions from reporters.
Asked about Arias, the winner of the 1987 Nobel Peace Prize for his work on a peace deal that ended Central America's civil wars, Gibson said: "I'm a fan."
The actor acknowledged buying a house in Guanacaste on the country's Pacific coast, and jokingly asked reporters if they wanted the address.