1. A drive support display device supporting a drive of a self-vehicle based on a detection result by an object detector regarding a nearby area of the self-vehicle, the device comprising: a receiver that receives object information from an external source, the object information identifying a nearby object existing in the nearby area of the self-vehicle; a determination section in a processor, the determination section determining whether the nearby object identified in the object information that is received by the receiver is detected by the object detector; and a display section in the processor, the display section providing a warning indicator when the determination section determines that the nearby object is an undetected nearby object that is not detected by the object detector, wherein the object information includes external source information that is received by the receiver from the external source via each of a vehicle-to-vehicle communication and a road-to-vehicle communication, the object information includes external vehicle information that is received by the receiver from an external vehicle via the vehicle-to-vehicle communication, and when the external vehicle information from the external vehicle is discontinued, the determination section determines whether the object detector has detected the nearby object based on the external vehicle information that has been received before discontinuation.