An efficient application of equipment capacity is an important factor for a company of today to survive under a extremely competitive market environment. However, many companies have made an great effort to increase an external capacity by putting much input such as time and money without scrutinizing an equipment efficiency. As a result of such increased equipment capacity, they have been faced with the problem of how to effectively deal with its excess capacity which is somewhat indispensible capacity for a company`s business and thus can not be completely eliminated in a real world Therefore, this paper is concerned with defining capacity factors in detail to get practicable application devices and deriving their cost to provide a useful financial information for a company`s management to make a sound investment decision. We present the real case study to show the applicability of the methodology we developed in this paper.