To provide the maintenance cost estimation system of a work vehicle capable of accurately estimating the cost of a maintenance contract for respective countries or respective regions.

This system is provided with a cost data base 11 storing the cost data of the component costs of a component unit, man-hours and wages, etc., required for the maintenance of performing repair and periodical inspection maintenance for respective machine kinds, an operation input means 12 for inputting respective estimation condition data required for a maintenance cost estimation such as the machine kind data of an estimation object and estimation item data for respective devices and respective components and inputting an economic coefficient for indicating economic indexes for the respective countries or respective regions and the operation load conditions of the work vehicle of the estimation object and an arithmetic means 13 for reading the cost data corresponding to the inputted machine kind data from the cost data base 11 and estimating and computing a maintenance cost for each prescribed time or each prescribed time period of the estimation object work vehicle by the cost data for which the cost data are corrected based on the economic coefficient and the operation load conditions.