A biomass fuel manufacturing plant includes: a separating section that separates oil and water from oil-containing wastewater discharged from an essential oil plant that refines essential oil from fruits containing fats and oils, and separates the oil and water into POME oil and treated water; a discharged oil supply line that supplies at least one of the POME oil, discharged oil at compressing discharged when compressing empty fruit bunches, and discharged oil at crushing discharged when crushing the empty fruit bunches, to at least one or more locations of a carbonization section that generates carbide by performing heat treatment with respect to the empty fruit bunches discharged from the essential oil plant and a fuel generation section that generates a fuel from the carbide.