In Korea, a proton linear accelerator complex is being built as a part of the 21st Century Frontier Projects. Contingent valuation method (CVM) is a main evaluation method of nonmarket goods for which markets either do not exist at all or do exist only incompletely. This study shows the method can be applied to the benefit assessment of the proton accelerator complex. Using the discrete choice CVM method, this study estimates the willingness-to-pay (WTP) of a would-be user for the proton accelerator complex as 20,133 won per month.