NOVELTY - A pre-hydrolysis liquid is processed by carrying out ethanol fermentation of pre-hydrolysis liquid which arises according to pre-hydrolysis of timber of pulp manufacture, and obtaining bioethanol and process liquid, taking out arabinose from the process liquid after ethanol fermentation, methane-fermenting the process liquid after taking out arabinose, and obtaining methane gas and methane fermentation drainage liquid.    USE - Processing of pre-hydrolysis liquid used for manufacturing bioethanol, arabinose and methane gas (all claimed).    ADVANTAGE - Treatment of pre-hydrolysis liquid is efficient.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) manufacture of bioethanol from pre-hydrolysis liquid which involves carrying out ethanol fermentation of pre-hydrolysis liquid which arises according to pre-hydrolysis of timber of pulp manufacture, and obtaining bioethanol and a process liquid, taking out arabinose from process liquid after ethanol fermentation, methane-fermenting the process liquid after taking out arabinose, and obtaining methane gas and methane fermentation drainage liquid;    (2) manufacture of arabinose from pre-hydrolysis liquid which involves carrying out ethanol fermentation of pre-hydrolysis liquid which arises according to pre-hydrolysis of timber of pulp manufacture, and obtaining bioethanol and a process liquid, taking out arabinose from process liquid after ethanol fermentation, methane-fermenting the process liquid after taking out arabinose, and obtaining methane gas and methane fermentation drainage liquid; and    (3) manufacture of methane gas from the pre-hydrolysis liquid which involves carrying out ethanol fermentation of pre-hydrolysis liquid which arises according to pre-hydrolysis of timber of pulp manufacture, and obtaining bioethanol and a process liquid, taking out arabinose from process liquid after ethanol fermentation, methane-fermenting the process liquid after taking out arabinose, and obtaining methane gas and methane fermentation drainage liquid.