The industrial structure of modern society consists of various fields, but still a large part is manufacturing based on large facilities. Therefore, various studies are being conducted to efficiently operate large facilities. Among other things, recent research on facility maintenance has evolved from Total Productive Maintenance (TPM), an enterprise-wide view of maintenance, to Reliability Centered Maintenance (RCM), a reliability-oriented maintenance method, and PHM (Prognostics and Health Management), which monitors the integrity of the facility and predicts failures to minimize maintenance-related Losses. However, research into the economic analysis of facilities is not yet active. In this paper, the process of calculating the maintenance cost using the reliability block diagram (RBD) and analyzing the economic value of the facility is presented.