To provide a reliably and efficiently applicable disaster countermeasure system for allowing easy recognition of operation instructing information for disaster countermeasure information.

When signals are transmitted/received via communication means among a plurality of computers 31, 41, 5, 6 each having a large display 45 and a monitor for displaying an action flow with a plurality of operation instructing information applicable to the status of disaster for coping with the disaster, signal contents transmitted/received are displayed in colors different from those of the action flow. Easy identification is allowed between the operation instructing information for coping with the disaster and the signal contents transmitted/received among the computers 31, 41, 5, 6 to achieve reliable and efficient coping in accordance with the easily identified operation instructing information and reliable and efficient processing of the easily identified signal contents.