The invention relates to a device of controlling running of a vehicle and a method. An adaptive cruise traveling control system is configured to control a speed of a host vehicle at a basic speed-control mode at which a set vehicle speed is set as a desired vehicle speed for an adaptive cruise traveling control function. The adaptive cruise traveling control system is also configured to control the host vehicle speed at a driver-intervention speed-control mode at which a limited vehicle speed of a road, on which the host vehicle is traveling, is set as the desired vehicle speed, when the desired vehicle speed has been set to the limited vehicle speed manually by a driver's operation made to a man-machine interface, under a condition where the limited vehicle speed has been detected.