The final, held Saturday in Yokohama, ended with a 32:12 victory for the South Africans. Among the winners, Handre Pollard scored 22 points, Makazole Mapimpi and Cheslin Colby both scored tries while for England, Owen Farrell kicked 12 points.
New Zealand came third after beating Wales yesterday.
It was South Africa's third World Cup win, equalling New Zealand's record.