A vehicle condition monitoring system for an unattended vehicle includes an initial setting storage means, an actual state detection means, a comparison means, and a reporting means. The initial setting storage means memorizes a predetermined initial setting of a vehicle, that is, a window setting, a light setting, a door lock setting and the like. The actual state detection means detects an actual state of the vehicle. The comparison means compares the initial setting and the actual state of the vehicle. The reporting means issues a report that identifies the existence of a difference between the actual state of the vehicle and the initial setting based on a result of a comparison. A portable device receives the report through a wireless communication system.