Disclosed is an agitating device (3) to be disposed in a batch-type vessel or the like. The agitating device (3) has an upper cover plate (5), a bottom cover plate (6), an impeller (7), an inner screen member (8), and first and second outer screen members (9, 10). When a mixed liquid including a dispersoid and a dispersion medium passes through liquid communication holes (19) of the inner screen member (8) and liquid communication holes (22, 25) of the outer screen members (9, 10) during the course where it flows outward from the impeller (7) to get out of an interplate space, the circumferential component of the flow vector of the mixed liquid is mostly eliminated to allow the mixed liquid to have substantially only the radial component. This prevents the generation of vortexes so as to apply a sufficiently high shearing force to the mixed liquid to effectively prevent the formation of macro bubbles in the mixed liquid.