Four decades have passed since the first application of deep mixing method. The total volume of stabilized soil in Japan from 1977 to March 2014 reached 77.4 million cubic meters for the wet method and 33.5 million cubic meters for the dry method. The success of deep mixing in Japan has been made possible by the timely and continued research and development. The paper describes the history of research and development in the past four decades in Japan and provides the information for the subjects that may benefit the deep mixing community worldwide.