Abstract: A centrifugal separator comprises a centrifugation chamber, gas inlet ports for introducing a gas into the centrifugation chamber so as to whirl the gas, a clean gas discharge pipe provided on the upper portion of the centrifugation chamber, and a guide member secured to the lower portion of the centrifugation chamber. The guide member has an annular groove, outer fine holes made in the groove, a guide portion projecting conically inward the centrifugation chamber, and an inner hole made in the center of the guide portion. A gas including particles is introduced into the centrifugation chamber, in which the particles are separated. The separated particles are trapped in the groove with gas, then discharged from the outer holes. The clean gas removed of the particles is guided by the guide member to direct to the gas discharge pipe, at the same time the particles with gas toward the guide member also are guided by the guide member to be subjected to the centrifugal force.