A traffic information creation method includes: a vehicle velocity detection step for detecting a vehicle velocity by a vehicle velocity sensor at a predetermined distance interval or a predeterminedtime interval; and a congestion degree detection step which detects the congestion degree in accordance with the vehicle velocity by referencing a stipulated velocity and a stipulated distance which have been decided in accordance with the congestion degree and the road type. The traffic information creation method creates traffic information for each link. When the link length is in the predetermined range, the congestion degree information corresponding to the fastest vehicle velocity within a preset start point distance from the link start is allocated to the link.