PURPOSE: To save energy and effectively utilize a resource by scouring a pulp material with a solvent and reutilizing recovered waste heat and treated waste water.

CONSTITUTION: A pulp material (B) such as waste paper recovered pulp or digested unbleached pulp is scoured with a solvent. In the process, impurities such as metallic materials or resins are separated and released from the pulp material (B) in a circulating water stream of a water washer 1 and the resultant pulp material is then fed to a gas-replaced filter 10 to separate inked water (C) in an inert gas. The obtained pulp material is simultaneously washed with hot water (K) and subsequently dehydrated to provide a dehydrated cake (D), which is then fed to a solvent circulation and contact device 17 composed of a solvent contact device, a gastight filter, a solvent distilling device and a desolvating device, scoured, converted into scoured pulp and further formed into paper with a papermaking device 43. Soft water (J) is converted into high-pressure steam (L) with a waste heat recovering boiler 46 additionally installed in an incinerator 44 for a disposed organic substance (T) during the treating process to supply heat to the distilling device, further used as the hot water (K) and fed to the gas-replaced filter 10 to effectively utilize the waste heat and the resource.