Provided is a wrong-way-driving suppression device and the like for suppressing wrong-way-driving of a vehicle on a one-way road using existing map data and an onboard device or the like.The wrong-way-driving suppression device according to the present invention includes: a current position acquiring unit for acquiring a current position of a host vehicle; a traveling direction acquiring unit for acquiring a traveling direction of the host vehicle; a map data acquiring unit for acquiring surrounding map data of the current position; a traveling status determination area setting unit for setting a determination area where a traveling status of the host vehicle is to be determined from the current position and the surrounding map data; a correct traveling direction storing unit for storing, as a correct traveling direction, a traveling direction of the host vehicle at the time of passing a connection point of an entrance-side connection road with a main line in the determination area, the entrance-side connection road connecting the main line and an entrance side of a rest facility; and a notification instructing unit for instructing a notifier to perform predetermined notification when an angle formed by a traveling direction of the host vehicle and the correct traveling direction is larger than or equal to a first threshold value in the determination area.