A road information sharing method according to the present invention is a road information sharing method for sharing the road information via a terminal device, the road information sharing method including the steps of storing sensor information acquired from a vehicle moving in accompaniment with the terminal device, detecting the road information from the sensor information on the basis of detection rules for detecting the road information, notifying a user about the road information detected, and prompting the user to make a judgment of necessity/unnecessity of registration about the detected road information, and storing the detected road information, if the detected road information is judged to be registration-necessary by the user.