To solve the problem that there is no useful information serving as a reference for a person who draws up a maintenance schedule, because information on the degree of a deterioration in an individual concrete structure and the rest of its life, information on a detour in the case of damage to the concrete structure, etc., serving as an index for drawing up the maintenance schedule for the concrete structure, exist only as distributed information but there is no useful information for the person who draws up the maintenance schedule, in the conventional planning of the maintenance schedule for the concrete structure existing in a road network for a specific area.

The maintenance schedule for the concrete structure existing in the road network for the specific area is output only by inputting information, such as the result of the simple detection of the concrete structure, information on the road network, traffic information and the locational condition of the concrete structure, which is already possessed by an institution for managing the road network for the specific area. This brings about a system for providing the information useful for the person who draws up the maintenance schedule.