In a bus control system for a semiconductor circuit, data is transmitted between first and second nodes over a network of buses. The bus controller is connected directly to the first node and includes: a route load detector which detects loads on routes that form at least one of a group of forward routes leading from the first to the second node and a group of backward routes leading from the second to the first node; a candidate route extraction circuit which extracts a candidate route from the group of routes so that loads on the routes that form the group become uniform; a route determining circuit which determines the route to transmit the data based on the candidate route and a predetermined selection rule; and a data communication circuit which transmits the data between the first and second nodes based on header information including route information indicating the route.