The present invention provides a novel method of two-dimensionally arraying ferritin on a substrate, which obviates the need for a metal ion for achieving linking between two adjacent ferritin. The present invention provides a method of two-dimensionally arraying ferritin on a substrate, wherein the ferritin has an amino acid sequence set out in SEQ ID NO: 1 on the outer peripheral surface; the surface of the substrate is hydrophilic; and the method includes a development step of developing a solution that contains a solvent, the ferritin, and 6.5 mM to 52 mM ammonium sulfate on the substrate, and a removal step of removing the solvent from the solution developed on the substrate.