To improve yield and quality (especially, a tear index) of a pulp in a method for producing the pulp by using a cooking assistant for a lignocellulose material.

The yield and the quality (especially, the tear index) can be improved by using an organic reducing material (preferably, thiourea or a thiourea derivative) as the cooking assistant in the method for producing the pulp by using the cooking assistant for the lignocellulose material. Another cooking assistant arbitrarily selected from a quinone-based material, a polysulfide, a surfactant and the like can be used therewith.