The invention discloses a culture medium filling device. The device is composed of a material pipe, a filling head and the like, the filling head structurally comprises a connecting column, a connecting cylinder, a movable buckle and a guiding mechanism, the connecting column is installed at the top of the connecting cylinder, the other end of the connecting cylinder is in threaded connection withthe guiding mechanism, the movable buckle is installed in the middle of the connecting cylinder, the guiding mechanism is composed of a threaded opening, a leveling plate, a first arc plate and a second arc plate, and the threaded opening is formed in the middle of the leveling plate. According to the device, a mode that metal wires cooperate with screen cloth is adopted, when a culture medium isfilled, a net bag can be straightened due to the fact that the culture medium is contained, materials fall vertically, and along with gradual reduction of the filling content of the culture medium, the metal wires recover gradually to be in a semicircular bag shape to hold residual culture medium liquid drops to avoid continuous dripping.