In this study, Japanese cedar was delignified using 20wt% different fatty acid sodium salt dissolved in glycerol at 250°C for 1h. The fatty acid sodium salt dissolved in glycerol simulated by-product of biodiesel production. In case of 4‒18 carbon chain length of fatty acid sodium salt, lignin content in Japanese cedar was decreased to about 10wt% from initial 36wt%. However, sodium salt whose length is under 3 carbon chain were less effective for delignification.Enzymatic saccharification of delignified Japanese cedar was conducted at 45°C. Behavior of enzymatic saccharification of Japanese cedar treated with sodium octanate, sodium myristrate, and sodium oleate were different, in spite of lignin content of substrates were same around 8wt%. It suggested that effect of residual sodium salt in deliginified Japanese cedar on saccharification was performed. As the result, it was found that enzymatic saccharification was promoted or impeded by type of sodium salt and their residual quantities.