To provide high yield pulp for printing paper from a plant raw material containing a large amount of pith, which has a non-wood plant raw material such as bagasse consists of 2/3 amount of rind (pelt) and 1/3 amount of the pith (medulla), for the improvement of brightness of the pulp, possibility of drainage control, significant improvement of yield, and formation of a low pollution production system.

The high yield pith pulp and high yield rind pulp capable of being used as the main raw material of middle quality and low grade printing paper, and having a high brightness and suitable drainage, are produced with low pollution by dividing the plant raw material (whole bagasse) containing a large amount of pith into the pith and rind in advance, lightly treating the separated pith and rind with a PA digesting chemical liquid (an alkaline solution of hydrogen peroxide), and then mechanically loosening the treated pith and rind.