To provide a cotton candy preparing device for preparing cotton candy in a good condition at all times irrespective of different heating conditions for granulated sugar and sugar candy, a cotton candy preparing device having a rotary pot formed of a pot upper portion and a pot bottom portion is provided, and the pot upper portion has a loading port at an upper end thereof and further tubular inner walls below the loading port, lower ends of the inner walls have a conically shaped expanded inclined portion that expands downwards, a plurality of plate-shaped ribs are provided on the expanded inclined portion so as to project towards a center of the rotary port, and lower ends of the ribs are brought into contact with a heating plate provided on an upper surface of the pot bottom portion or forms a slight gap between the heating plate and themselves.