An automatic driving device includes a position acquisition unit configured to acquire position information on another automatically-driving vehicle and another manually-driving vehicle, a route searching unit configured to search a route, a calculation unit configured to calculate a ratio of the number of the other automatically-driving vehicles to a total number of all other vehicles on the route for each route based on the position information on the other automatically-driving vehicle and the position information on the other manually-driving vehicle when a plurality of routes is searched, a selection unit configured to select the route wherein the other automatically-driving vehicle ratio calculated by the calculation unit is highest as a route for the host vehicle to travel, and a control unit configured to control automatic driving of the host vehicle so travel along the selected route.