A straw splitter for longitudinally splitting pieces of cereal straw into separated strands for use in making a panel, board or beam is provided. A cutting shear roller and a gripping shear roller are rotatable around their longitudinal axis at different circumferential speeds. The pieces of straw are split due to shear between the cutting shear roller and the gripping shear roller. The shear rollers each comprise parallel grooves with cutting edges oriented at a predetermined angle to the roller axis such that the grooves of the gripping shear roller cross the grooves of the cutting shear roller providing a scissoring action for splitting the straw into long strands.