A quantum device is constituted from a two-dimensional array of quantum dots formed from metal atom aggregates contained in a metalloprotein complex. The metalloprotein is arranged on the surface of a substrate having an insulation layer with a pitch of the size of the metalloprotein complex. The diameter of the metal atom aggregates used in the quantum device is 7 nm or smaller, and the pitch of the metalloprotein complex is preferably from 11 to 14 nm.