Provided is a method of producing a structure for producing a casting, including: a process (I) of obtaining a slurry composition containing an organic fiber, an inorganic fiber, a thermosetting resin, and water; a process (II) of obtaining a fiber laminate by subjecting the slurry composition to papermaking; and a process (III) of dehydrating the fiber laminate and thereafter drying the resultant, in which the process (I) includes a process (I-1) of beating a mixture containing the organic fiber and water, a process (I-2) of mixing the mixture obtained in the process (I-1) and water, and a process (I-3) of mixing the mixture obtained in the process (I-2) and the inorganic fiber, the thermosetting resin is mixed in at least any of the process (I-1), the process (I-2), and the process (I-3), and an average fiber length of the inorganic fiber in the structure for producing a casting is 1 mm or longer and 5 mm or shorter.