An agitation apparatus (100) has a rotation shaft (150) provided along the central axis of a cylindrically shaped agitation vessel (102). To the rotation shaft (150), a substantially cylindrically shaped agitation member (104) is attached. The agitation member (104) has an outer diameter smaller than the inner diameter of the agitation vessel (102), and rotates concentrically with the inner circumferential surface of the agitation vessel (102). The agitation member (104) has a plurality of through holes (162, 164) formed in radial directions therethrough. The through holes (164) formed in an upper portion of the agitation member (104) are larger than the through holes (162) formed in a lower portion of the agitation member (104).