The purchase contract for government-supplied materials, which means materials provided by the owner in public construction works, has various delivery conditions. Controversy has continued between public agencies such as the Public Procurement Service and construction contractors over the appropriateness of application of the purchase contract with on-site installation conditions, and the Anti-Corruption and Civil Rights Commission (ACRC) made recommendations in 2012. Nevertheless, public agencies continue to actively apply product purchase contracts with on-site installation conditions. In this study, total on-site installation related costs was defined as the sum of direct labor costs, equipment expenses, and other related interlocking costs. As a result of analyzing the total on-site installation related costs of government-supplied materials from the actual construction cost data of 25 construction works, it accounted for an average of 4.49% of the estimated price. If the ratio of 4.49% to the 37.5 trillion won estimated as the average amount of public construction projects in Korea is reflected, the annual on-site installation related costs is about 1.6838 trillion won. It can be confirmed that the proportion of on-site installation related costs of government-supplied materials in the construction market is substantially significant.