These materials related to the Nishihama Salt Farm were donated to Ako City in Heisei 29 (2017) by Nihonkaisui Co. and include over four thousand items such as pictures, diagrams, maps, and related materials the company inherited from the Nishihama Salt Producers Cooperative Association. The collection includes numerous materials from the period between Showa 20 (1945) and Showa 40 (1965) that show the transition from irihama salt farms to ryukashiki salt farms (which made use of pumps, a slope, and sprinklers), and then to salt production via the ion exchange membrane method. Their detailed account of the evolution of modern salt production technology makes them precious records. Currently, work such as creating a ledger including all the items and preparing them to be used as research materials is underway. Future research that will uncover the entire picture of the information contained in these materials is highly anticipated.