An end point speed at an end point of inertial travel that a vehicle is controlled to perform in a short section li is calculated using a weight, a start point speed, slopes, and a horizontal distance, based on a change in energy of the vehicle or an acceleration of the vehicle in the short section. In a case where the calculated end point speed is within a speed range, the vehicle is controlled to perform inertial travel in the short section. In this way, the speed of the vehicle in a case where the vehicle is controlled to perform inertial travel can be accurately calculated and the vehicle can be prevented from deviating from a set speed range at an early stage even when controlled to perform inertial travel, thereby increasing the distance traveled by inertial travel and effectively increasing fuel economy.