An agitation apparatus (100) has a substantially cylindrically shaped agitation vessel (102); a rotation shaft (150) provided along the central axis of the agitation vessel (102); a substantially cylindrically shaped agitation member (104) having an outer diameter smaller than the inner diameter of the agitation vessel (102) and being fitted to the rotation shaft (150) so as to rotate concentrically with an inner circumferential surface of the agitation vessel (102); and a plurality of through holes (162, 164) formed through the agitation member (104) in radial directions of the agitation member. In the agitation apparatus (100), a gap between the inner circumferential surface of the agitation vessel (102) and the outer circumferential surface of the agitation member (104) is partially varied along a vertical direction of the agitation member (104). For example, the gap between the inner circumferential surface of the agitation vessel (102) and the outer circumferential surface of the agitation member (104) is wider at a lower portion (S2) of the agitation member (104) than at an upper portion (S1) of the agitation member (104).