To provide a method for producing kraft pulp, by which the pulp can be obtained in a high yield and in a high pulp strength (especially a tensile index), and to provide an apparatus for producing the same.

In this method for producing the kraft pulp, the cooking degree of a pulp raw material is lowered to enhance a kappa number. The pulp raw material is mechanically beat and perfectly pulped with a refiner at the exit of a continuous digester and before or in a refining process to produce the kraft pulp in a high yield. The pulp raw material is mechanically beat with the refiner in a pulp concentration of 10 to 20% to accelerate the fibrillation of the pulp fibers, thereby enabling the production of the pulp having a high strength and containing few knotted fibers. Thus, the employments of steam / a cooking agent liquid in the cooking process can be reduced by lowering a cooking degree in the cooking process. The kraft pulp having a high pulp strength (especially a tensile index) can be produced by beating the pulp raw material with the refiner in a high pulp concentration.