An opto-electronic apparatus with a metallic structure is provided, and includes a light-permissible medium and a metallic structure. The metallic structure is disposed inside or over the light-permissible medium, and is formed from arrangement of at least one metallic unit. Each metallic unit includes at least three metallic blocks of which centers of mass define a polygon. After passing through the metallic structure, an electromagnetic wave has a distribution curve of transmittance versus wavelength, wherein the distribution curve has at least one transmittance peak value corresponding to at least one wavelength in a one-to-one manner. The area of the polygon is smaller than or equal to λ2, the minimum side length (dmin) is smaller than or equal to λ, and an averaged width (W) satisfies the following relationship: 0.01λ