The invention discloses a material mixing device, and particularly relates to a stirrer for experiments. The stirrer for the experiments comprises a motor, a supporting platform, a finely mixing cover, adjusting screws, height adjusting blocks, a fixing pin and a stirring knife, and is characterized in that: the motor is connected and fixed on the supporting platform through bolts, the stirring knife is fixed together with a rotating shaft of the motor through the fixing pin, the finely mixing cover is fixed on the lower surface of the supporting platform through bolts, four legs of the supporting platform are each provided with a middle hole, the height adjusting blocks can respectively slide in the middle holes, and the adjusting screws on the four legs of the supporting platform can fix the height adjusting blocks; and the special finely mixing cover of the stirrer and a six-layer stirring blade structure of the stirrer can make materials more fully mixed, and experiment-required precision can be achieved.