The invention provides a vehicle travel assist device for preventing a vehicle from exceeding a target stop position when a wheel passes through a step. The vehicle travel assist device is provided with: a vehicle travel control device that controls travel of a vehicle toward a target stop position; a travel state acquisition device that acquires travel state information indicating a travel stateof the vehicle; and a step position estimation device that acquires step position information indicating the position of a step on the travel path of the vehicle. The travel state information includesvehicle position information indicating positions of the vehicle and each wheel. The vehicle travel control device determines whether the vehicle exceeds a target stop position or not when a target wheel of the vehicle passes a step based on the step position information and the vehicle position information. When it is determined that the vehicle exceeds the target stop position, the vehicle travel control device changes the target stop position in order to prevent the target wheel from passing through the step, or stops the vehicle by generating a braking force before the target wheel passesthrough the step.