A method for operating an apparatus for predicting confirmed cases of an infectious disease is provided. The method comprises predicting infectious disease information per country, including an infection risk per country, expected number of entrants per country, and number of imported cases per country, based on collected epidemic statistics data per country and inflow data between a corresponding country and a destination country, grouping two or more countries based on geographic or economic relevance, and correcting the infectious disease information per country of countries within a grouped group according to a contagion risk impact set depending on a correlation between the countries within the group, and predicting total number of imported cases flowing into the destination country by re-correcting the infectious disease information per country through applying a correlation for the confirmed cases of the infectious disease between groups to the infectious disease information per country.