In industrial machine abnormality diagnosis, if the machine is diagnosed to have abnormality, then sensor data from the machine needs to be sent to a management center for causal analysis. However, since machines operated at a remote site cannot always communicate with a management center, it has been found that, in some cases, sensor data that has failed to be sent from a machine remains in the memory of the machine, resulting in lack of available memory capacity. In view of this, the present invention determines beforehand whether the diagnosed machine will run out of available memory capacity before the completion of sending the amount of sensor data required for causal analysis for the machine, and instructs a maintenance person to recover memory. This determination as to whether the machine will run out of available memory capacity before the completion of sending the amount of sensor data required for the causal analysis for the machine, is made as follows: (1) first, the machine predicts the run-out date on which the machine will run out of memory capacity for storing sensor data generated in the machine, and sends a notification of the predicted run-out date to the management center for the machine; and (2) next, from the amount of sensor data required for the causal analysis and the reception rate of sensor data, the management center calculates the number of days required to retrieve the necessary data for the causal analysis and determines whether the management center can retrieve the data by the predicted run-out date.