An acquisition unit acquires weather and marine data indicating a ship voyage schedule that serves as a reference, actual performance data, fuel consumption data, and weather and marine conditions the ship has encountered during a voyage. A time difference data generation unit calculates the difference between the time indicated by the reference data and the time indicated by the actual performance data for each of the journeys between ports. Projected fuel consumption calculation unit calculates projected fuel consumption for each of the journeys between ports based on the reference data, weather and marine data and fuel consumption data. Fuel consumption difference data generation unit calculates the difference between the projected fuel consumption and the actual fuel consumption amount indicated by the actual performance data for each of the journeys between ports.