PROBLEM TO BE SOLVED: To provide a method for drying and regenerating casting sand, which can facilitate to obtain, by a simple device, dried regenerated sand that is made from recovered degraded sand (used casting sand) and does not contain moisture and thus does not have a limit for usable period.SOLUTION: The method includes the steps of: molding a water soluble mold (hereafter called mold) using casting sand added with a binder aqueous solution made of a water-soluble inorganic salt (hereafter called binder aqueous solution); casting a material using the mold; removing (rinsing) the sand from a cast article using a cleaning solution; recovering the casting sand (hereafter called recovered degraded sand) through settling precipitation from the used cleaning solution containing the degraded sand that is generated during the rinsing; and drying and regenerating the sand. The recovered degraded sand 16A is placed into a drying treatment cylinder 27 having a porous drainage plate 29 at the bottom, the opening side of the drying treatment cylinder 27 is tightly sealed, and is dried by blowing pressured air thereinto to produce the dried regenerated sand 16B.