The invention relates to an agitating device, in which a hyperboloid agitating body (6) is connected to a drive mechanism (2, 3) by means of a shaft (4). Several ribs (7) running from the circumferential boundary (Ur) in the direction of the shaft (4) are provided on the upper side (O) of the agitating body (6). According to the invention, the efficiency of the agitating device may be improved, whereby a height (h1) of the ribs (7) at least incrementally increases from the circumferential boundary (Ur) of the agitating body (6) in the direction of the shaft (4).