A first telegraphic message collection unit (101) collects telegraphic messages travelling across a first network (50) and stores the same in a first storage unit (103). A second telegraphic message collection unit (102) collects telegraphic messages travelling across a second network (60) and stores the same in a second storage unit (104). A telegraphic message association unit (105) retains a mapping table in which the correlation, or similar, between telegraphic messages travelling from the first network (50) to a gateway device and telegraphic messages travelling from the gateway device to the second network (60) is defined. The telegraphic message association unit (105) references the mapping table and associates the telegraphic messages stored in the second storage unit (104) with the telegraphic messages stored in the first storage unit (103). From the result of the above-mentioned association, a state analysis unit (106) determines whether or not telegraphic message transfer is occurring in a normal manner between the first network (50) and the second network (60).
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