A management apparatus executes: receiving from a given communication apparatus where a fault has occurred, fault information; selecting a given flow that passes through the given communication apparatus from among a group of flows on the basis of the identification information of the given communication apparatus included in the fault information; determining whether the communication pattern of the given flow is similar to the given time series data indicating the change over time of the traffic within a period from a set period prior to the fault occurrence date and time to the fault occurrence date and time for the given flow; calculating the certainty that the given flow has been transmitted on the fault occurrence date and time on the basis of a frequency of appearance of the traffic of the communication pattern determined to be similar; and outputting calculation results.