(1)The sulfite contents in the sulfite liquor are determined at the several steps during the digestion with Karamatsu by means of three kinds of the determination method. (2)The author stated that Oeman's method is allowed to use as the simple and quick method during the all digestion steps and by Klason's method can not bedetermined the contents of f-SO_3 and t-SO_2 at the last step of the cookin gand by Partansky's method can not the content of c-SO_2 or half free SO_2 be determined.(3) One part of the effects of the seasoning as the sawdust of Karamatsu heart wood upon the digestion is explained by means of comparing the sulflte contents in the liquors.