By evaluating a distance starting from a start point to a unit on the map, the strength of an enemy character to be encountered, the degree of difficulty for an object to pass through a gate, etc., a unit score is calculated for each route. This unit score can be taken as an index of the degree of difficulty for the object to arrive at a unit from the start point. By using this unit score, the game elements can be appropriately disposed on the map in accordance with the degree of difficulty.