A vehicle-onboard ETC apparatus capable of conducting ETC information communication includes a vehicle speed detector for detecting a speed of a motor vehicle which passes through a toll gate station equipped with an ETC system, a communication unit for exchanging ETC information for settlement of toll charge/payment with the toll gate station upon passing therethrough, a measuring unit for measuring reception field intensity of the received ETC information within a communication coverage area, and a decision unit for making decision on the basis of the detected vehicle speed and the measured reception field intensity as to a location within the communication coverage area where ETC information communication can be started while sustaining favorable field intensity for signal reception at the detected vehicle speed, to thereby allow the communication means to perform communication processing on the basis of the result of the above decision.