A method of extracting konjac flour from the tubers of Amorphophallus konjac, wherein, in producing konjac flour by the wet comminution of the tubers of Amorphophallus konjac, the konjac flour separated after the comminution operation is submitted to further polishing to remove the tachiko (dust from Amorphophallus konjac) which adheres to the surface of the konjac flour.