To provide a method for producing anhydrous gypsum powder by effectively using a gypsum board waste material, by which anhydrous gypsum powder having good flowability, not causing plugging in a process line when it is used industrially, and easy to be discharged from a tank, a silo, a hopper or the like is produced.

The method for producing anhydrous gypsum powder includes adding a pulverization aid to anhydrous gypsum obtained by subjecting a gypsum board waste material to a heat treatment, and pulverizing the resulting mixture. In the method, a liquid containing propylene glycol is used as the pulverization aid.