A vehicle driving assist device comprises a risk determination region setting unit configured to set a risk determination region for calculating a risk degree that decreases as a distance outward from a center of the oncoming moving body in a width direction of the oncoming moving body increases. The risk determination region setting unit is further configured to set the risk determination region such that the risk degree is zero at a distance in a vehicle width direction between the vehicle and the oncoming moving body matching an average distance. The average distance is calculated based on distances in the vehicle width direction between the vehicle and oncoming moving bodies acquired every time the vehicle passes by the oncoming moving bodies.