In a navigation apparatus in a vehicle, a user designates a validating route, which is stored in a memory device. A control unit invalidates a predetermined function of the navigation apparatus at a start-up, which is for the first time after an in-vehicle battery is connected or which results from turning on of a power source. Use of the navigation apparatus by the user is thereby disturbed. When the control unit determines that a route, which the vehicle has traveled through, is included in the previously designated validating route stored in the memory device, the control unit re-validates the invalidated predetermined function.