Abstract: An apparatus is equipped with first and second rotary shaft 3, 4 and a plurality of disks 40, 50 provided upright at equal intervals on the respective rotary shaft. The disks are heated or cooled from the inside, and a raw material is heated or cooled by bringing it into contact with the disk surfaces. Scraper members 45, 45? and 55, 55? that enter between the surfaces of the facing adjacent disks to scrape the raw material are fixed to each of the disks 40, 50. The first and second rotary shafts 3, 4 are rotated at unequal speeds such that the scraper members approach the facing disk surfaces with trajectories drawn thereon varying, so that the raw material that has adhered to the disk surfaces can be effectively scraped off.