Correspondence information has a plurality of records in each of which a first warning type and a first malfunction cause type are associated with each other. Malfunction information has a plurality of second malfunction cause types. A weighting unit determines, by using the malfunction information and the correspondence information, a count of second malfunction cause types each corresponding to the first malfunction cause type. The scoring unit gives a score to the first warning type corresponding to the first malfunction cause type according to the determined count, and generates weighting information in which the first warning type and the score are associated with each other. The scoring unit gives the score having been given to the first warning type to a second warning type corresponding to the first warning type of the weighting information, the analysis result information including the plurality of second warning types.