Provided is a cell wall or cell membrane disrupting device whereby cell walls and/or cell membranes of microorganisms, algae and the like contained in organic sludge and the like are disrupted, the device comprising a fixed disc, a rotating disc, a rotating shaft for driving of the rotating disc, a pressure reducing means and a housing, wherein at least one pair of the fixed disc and rotating disc are disposed facing each other, the center section of the fixed disc has a hollow section that is larger than the outer diameter of the rotating shaft passing through the center section, shearing force generated between the rotating disc and the fixed disc is applied to a target fluid having a water content of 89% or higher that has been loaded into the device, and the pressure inside the cell wall or cell membrane disrupting device is reduced to no greater than - 0.08 MPa by the pressure reducing means. The device can contribute to increasing biogas, reducing sludge, culturing of algae, plant cultivation and cultur
