A motheye mold fabrication method of at least one embodiment of the present invention includes the steps of: (a) preparing an Al base in which an Al content is less than 99.99 mass %; (b) partially anodizing the Al base to form a porous alumina layer which has a plurality of very small recessed portions; (c) after step (b), allowing the porous alumina layer to be in contact with an etchant which contains an anodic inhibitor, thereby enlarging the plurality of very small recessed portions of the porous alumina layer; and (d) after step (c), further anodizing the Al base to grow the plurality of very small recessed portions.