PURPOSE: To provide a centrifugal thin film drying apparatus which can sufficiently carry out drying treatment even for a treatment liquid to become a slurry with high viscosity, w4' can suppress the increase of film thickness in a slurry region even in the case the treatment liquid containing soluble solid matters is dryed and powdered, certainly prevents deterioration of thermal conductivity in a thermal transmission face to produce uniform powder, and can carry out treatment stably and improve the ratio of operation.

CONSTITUTION: A rotary shaft 29 is installed in the center position of a vertically long, and cylindrical heating trunk 21. Centrifugal force is applied to a treatment liquid which is supplied to the heating trunk 21 by blades 35 attached radiately to the rotary shaft 29 to form a thin film on the inner circumference of the trunk 21. Cut parts 38 are formed in the edge parts of the blades 35 facing the inner circumference of the heating trunk 21. In the case powder produced by heating, concentrating, and drying the treatment liquid is scraped away from the inner circumference of the heating trunk 21 by the blades 35, the plane pressure applied to the slurry rises due to the cut parts 38 and the slurry turbulence is lessened.