Abstract: Phenols such as cresol, phenol and xylenol etc. are obtained by thermal decomposition of a lignin-containing material in a state of a mixture of the lignin-containing material and a double ring aromatic hydrocarbon solvent.Spent liquid of a solvolysis pulping process can be used as the lignin-containing raw material in the present invention for manufacturing phenols, and the phenols obtained can be utilized as the solvent in the solvolysis process resulting in cost reduction in the pulp production process by self-supplying the necessary solvent in the solvolysis process.