A preprocessing unit calculates a square sum SJ(t.sub.n) of jerk J, and a driving characteristic calculation unit determines whether the jerk square sum SJ(t.sub.n) is equal to or above a predetermined threshold value. The position/traveling direction determination unit determines the position and traveling direction of the vehicle. A troublesome driving place determination unit records an intersection at which the jerk square sum SJ(t.sub.n) is calculated to be equal to or above the predetermined threshold value and the traveling direction of the vehicle at that time in association with each other in a troublesome driving place database. With reference to the troublesome driving place database, the troublesome driving place determination unit then calculates the risk cost at each intersection around the vehicle for each traveling direction. It is therefore possible to perform route guidance taking the driver's personal feeling into an account.