PURPOSE: To economically advantageously recover all or almost all of rare earth values from gypsum by treating water-insoluble components containing rare earth elements obtained from the gypsum by a solution containing carbonate ions and mineral acid and recovering the rare earth elements from the solution.

CONSTITUTION: The gypsum is dissolved in water and the insoluble components containing the rare earth elements are obtained. The insoluble components are digested by the mineral acid and the solution of rare earth salt is obtained. Then, by recovering the rare earth elements from the solution and processing the insoluble components by the solution containing the carbonate ions, the rare earth values contained in the gypsum are obtained. The insoluble components are processed by the carbonate ions by adding the carbonate ions to salt water for gypsum dissolution or bringing the insoluble component into contact with the solution containing the carbonate ions. The processing by the carbonate ions can be performed after the recovery of the insoluble components and before digestion by the mineral acid or simultaneously with the dissolution in the salt water of the gypsum by adding the carbonate ions to the salt water there.