Chestnut wood shavings were extracted with hot water to prepare tannin-free wood sample and crude tannin solution, which were cooked by the neutral sulfite method. From the ligninsulfonate and tanninsulfonate spent liquors, barium salts of ligninsulfonic acid (HLS) and tanninsulfonic acid (HTS) were isolated and purified according to the dicyclohexylamine method established by Tachi I. et all. The BaLS and BaTS isolated were separated into some fractions by the fractional precipitation method, and each fraction was examined for the percentage weight and the methoxyl content (results, Table 2). Fractional samples of HLS and HTS were prepared by passing each fraction of BaLS and BaTS through a cation exchange resin column, and were studied for the ultraviolet absorption (results, Fig. 3, Fig. 4, and Table 2), and for the precipitate forming action with glycolchitosan or β-naphthylamine (results, Table 3). HTS behaved itself like HLS in all stages of the isolation, so that it is important to use spent liquor obtained from tannin free wood sample to prepare a pure HLS preparation. Methoxyl content of these BaLS fractions was very little as compared to that of BaLS from the acid sulfite spent liquor reported already by other workers. The methoxyl method for the quantitative determination of HLS seemed to be carried out with a little disturving by HTS, because HTS contained little methoxyl group. The colloid titration method established by Senju R. et all gave an exact result for determination of the higher molecular fractions, however, for the lower molecular fractions, it gave too small values. HTS consumed glycolchitosan as well as HLS did, so that it was clear that HTS disturves the colloid titration method. The ultraviolet absorption method and the β-naphthylamine method seemed to be unsuitable for the quantitative determination of HLS in the neutral sulfite spent liquor.