A method for producing a hydrocarbon oil, comprising: a step of obtaining a hydrocarbon oil containing a catalyst fine powder derived from a catalyst by a Fischer-Tropsch synthesis reaction using a slurry bed reactor holding a slurry containing a liquid hydrocarbon and the catalyst suspended in the liquid hydrocarbon within the slurry bed reactor; a step of fractionating the hydrocarbon oil into at least one distilled oil and a column bottom oil containing the catalyst fine powder using a rectifying column; a step of transferring at least part of the column bottom oil to a storage tank, and sedimenting the catalyst fine powder to a bottom of the storage tank to capture the catalyst fine powder, said storage tank comprising a structure for suppressing movement of the catalyst fine powder sedimented to the bottom of the storage tank in the bottom of the storage tank, said structure being selected from the group consisting of a corrugated plate 20 installed on a flat bottom plate, a depression 22 on the bottom plate, a partition plate 24 on the bottom plate, an entangled fibrous structure 26 installed on the bottom plate, a structure having a mesh 28 above the bottom plate or a plate-like body 30 having a funnel-shaped structure having an inclination from the periphery toward the center and an opening in the center; and a step of transferring a residue of the column bottom oil from the rectifying column to a hydrocracker, and/or transferring a supernatant of the column bottom oil in which the catalyst fine powder is captured in the storage tank from the storage tank to the hydrocracker to hydrocrack the residue of the column bottom oil and/or the supernatant of the column bottom oil using the hydrocracker. a step of obtaining a hydrocarbon oil containing a catalyst fine powder derived from a catalyst by a Fischer-Tropsch synthesis reaction using a slurry bed reactor holding a slurry containing a liquid hydrocarbon and the catalyst suspended in the liquid hydrocarbon within the slurry bed reactor; a step of fractionating the hydrocarbon oil into at least one distilled oil and a column bottom oil containing the catalyst fine powder using a rectifying column; a step of transferring at least part of the column bottom oil to a storage tank, and sedimenting the catalyst fine powder to a bottom of the storage tank to capture the catalyst fine powder, said storage tank comprising a structure for suppressing movement of the catalyst fine powder sedimented to the bottom of the storage tank in the bottom of the storage tank, said structure being selected from the group consisting of a corrugated plate 20 installed on a flat bottom plate, a depression 22 on the bottom plate, a partition plate 24 on the bottom plate, an entangled fibrous structure 26 installed on the bottom plate, a structure having a mesh 28 above the bottom plate or a plate-like body 30 having a funnel-shaped structure having an inclination from the periphery toward the center and an opening in the center; and a step of transferring a residue of the column bottom oil from the rectifying column to a hydrocracker, and/or transferring a supernatant of the column bottom oil in which the catalyst fine powder is captured in the storage tank from the storage tank to the hydrocracker to hydrocrack the residue of the column bottom oil and/or the supernatant of the column bottom oil using the hydrocracker.