The present invention provides a vehicle display device capable of causing a driver to determine which function contributes to improvement in consumption efficiency when a plurality of efficiency improvement functions related to consumption efficiency are provided. The actual improvement effect of the three efficiency improvement functions of the free running, the idling stop, and the energy-saving driving mode is calculated, and the efficiency improvement functions can be displayed on the improvement effect display unit in comparison with each other. Therefore, the driver can confirm which ofthe plurality of efficiency improvement functions contributes to the improvement of the consumption efficiency. When the maximum improvement effect when the ideal driving in which the respective efficiency improvement functions can maximize the function is calculated and displayed, the driver can specifically understand the margin of the improvement effect of the efficiency improvement function of each efficiency improvement function. Therefore, the contribution of each efficiency improvement function to the consumption efficiency is reflected in the driving operation to achieve further improvement in consumption efficiency.