Disclosed is a rotating classifier which can retain high classification performance and in which blockages caused by biomass and the like are unlikely. The rotating classifier is characterised in: having a comb-shaped protruding section (36) which has gaps along the circumferential direction of a rotating classifier fin (13), and which is on the upper section of the rotating classifier fin (13) protruding towards a fixed member (27) side; a first gap (42) being provided between the upper end section of the comb-shaped protruding section (36) and the lower surface of the fixed member (27); a second gap (43) formed between a protruding section (36a) and an adjacent protruding section (36b) being connected to the first gap (42); and an air current being generated by the rotation of the rotating classifier fin (13), said air current travelling through the first gap (42) and the second gap (43) from the radially outward side to the radially inward side of the comb-shaped protruding section (36).
