Abstract: An improved apparatus and method for manufacturing ground wood pulp from ligno-cellulose containing wood block material by forcing the block material to be ground against the end surface of a rotatably mounted grinding disc which has projecting grinding means in the shape of elevations or ridges located on the disc end surface which define grooves directed towards the end surface circumference. The apparatus includes a pressure plate for pressing the block material along a longitudinal side against the disc end surface with the fibers directed outwardly from the center of the grinding disc and toward the periphery of circumference of the disc while the fibers are separated. In this manner the fibers are oriented in the same direction as the edges of the elevations or ridges which carry the fibers radially outward and the elevation edges engage the block fibers under a movement component which is transverse to the longitudinal direction of the fibers.