In considering cost reductions, it is natural to postpone equipment replacement until innovative equipment is made available, if it will appear in the near future. On the other hand, if new equipment with these characteristics is not made available in the near term, existing equipment is upgraded with similar products. This study discusses equipment replacement where innovative technological advances occur together with gradual technoiogical advances. It aims to clarify theoretically and experimentally the above equipmellt replacement behavior by using "Control Limit Policy". Next, we give apractical replaK:ement decision method using centro} Iimit policy when the appearance time of innovative equipment is forecasted. This study is significant in the sense of being able to show that control limit policy can propose not only a convenient metho d in actual replacement decisions, but also an effective method to explain the qualitative aspects of equipment replacement behavior.