A travel time data processor extracts a link that is present in the neighborhood of a target link, as a reference link. The travel time data processor selects an identical time zone of the reference link that is identical with the time zone of the target link in which the number of sample data is less than a reference number, and searches for another time zone having similar statistical data to that of the selected time zone. The travel time data processor adds the number of sample data in a time zone of the target link corresponding to the searched another time zone of the reference link to the number of sample data in the time zone of the target link that is equal to or less than the reference number, and generates statistical data from the summed-up sample data.