Provided is a soundproofing structure including: a plate-like member which has a plurality of through-holes passing therethrough in a thickness direction, in which in a case where an average opening diameter of the through-holes is 0.1 μm or greater and less than 100 μm, and in a case where the average opening diameter of the through-holes is set as phi (μm) and a thickness of the plate-like member is set as t (μm), an average opening ratio rho of the through-holes is greater than 0 and less than 1 and falls in a range where a center is rho_center=(2+0.25×t)×phi−1.6, a lower limit is rho_center−(0.052×(phi/30)−2), and an upper limit is rho_center+(0.795×(phi/30)−2).