In this paper, we evaluate a heuristic route guidance method that individually provides incentives to tourists to encourage detours and reduce traffic congestion. Traffic congestion caused by an excessive influx of tourists into sightseeing areas has become a serious issue. Although various route guidance methods have been studied, most of them only consider travel time and distance to the destination, and do not consider congestion on the road as a whole. As a result, traffic congestion may still occur on specific roads, even if individual routes are optimized. We proposed a method to reduce overall congestion by determining incentives for tourists individually and directing them to less congested detour routes. From the results of multi-agent simulation using artisoc Cloud, we confirmed that the proposed method can guide tourists to less congested routes with less total incentives and computation time compared to the route guidance method using random search and genetic algorithm (GA).