A unit for smoothly switching from auto-drive to manual drive for a vehicle provided with an auto-drive mode. To perform auto-drive, an auto-drive ECU controls steering wheel, brake, and accelerator actuators in accordance with signals from a route recognition/obstruction check sensor, a GPS and the like. When an interface (switch) for switching to the manual drive is operated, the auto-drive ECU evaluates running stability/instability in accordance with signals from various running safety devices and sensors for detecting a variation in vehicle state, and if the vehicle is in an instable state, prohibits a shift to the manual drive, even when the vehicle is running on a straight road.