A vehicle device used for a vehicle, comprising: a data acquisition unit configured to acquire data successively transmitted from outside a subject vehicle via communication; characterized in further comprising; a compensation unit configured to perform a compensation of a data loss resulting from unsuccessfully acquiring of data in the data acquisition unit by using data already acquired by the data acquisition unit, generate assistive data used for travel assistance of the subject vehicle, and associate with the assistive data a compensation implementation value indicating an implementation of the compensation; and an output unit configured to output the assistive data and the associated compensation implementation value to a travel assistance device for performing the travel assistance when the compensation unit generates the assistive data by compensating the data loss; and the travel assistance device, wherein the travel assistance device includes: an assistance function unit including a plurality of automatic driving functions each perform the travel assistance; and a usage determination unit configured to determine whether to use the assistive data for the travel assistance based on the compensation implementation value associated with the assistive data, wherein each of the plurality of automatic driving functions has a predetermined threshold value for the compensation implementation value, wherein the usage determination unit determines whether the compensation implementation value exceeds the predetermined threshold value of each of the plurality of automatic driving functions, and wherein the assistance function unit determines not to use the assistive data for the automatic driving function when the usage determination unit determines that the compensation implementation value exceeds the predetermined threshold value of the respective automatic driving function. a data acquisition unit configured to acquire data successively transmitted from outside a subject vehicle via communication; characterized in further comprising; a compensation unit configured to perform a compensation of a data loss resulting from unsuccessfully acquiring of data in the data acquisition unit by using data already acquired by the data acquisition unit, generate assistive data used for travel assistance of the subject vehicle, and associate with the assistive data a compensation implementation value indicating an implementation of the compensation; and an output unit configured to output the assistive data and the associated compensation implementation value to a travel assistance device for performing the travel assistance when the compensation unit generates the assistive data by compensating the data loss; and the travel assistance device, wherein the travel assistance device includes: an assistance function unit including a plurality of automatic driving functions each perform the travel assistance; and a usage determination unit configured to determine whether to use the assistive data for the travel assistance based on the compensation implementation value associated with the assistive data, an assistance function unit including a plurality of automatic driving functions each perform the travel assistance; and a usage determination unit configured to determine whether to use the assistive data for the travel assistance based on the compensation implementation value associated with the assistive data, wherein each of the plurality of automatic driving functions has a predetermined threshold value for the compensation implementation value, wherein the usage determination unit determines whether the compensation implementation value exceeds the predetermined threshold value of each of the plurality of automatic driving functions, and wherein the assistance function unit determines not to use the assistive data for the automatic driving function when the usage determination unit determines that the compensation implementation value exceeds the predetermined threshold value of the respective automatic driving function.