In an image pickup device, a step of forming an embedded plug includes a step of forming a connecting hole in the insulation film in which the embedded plug is to be formed, a metal layer deposition step of depositing a metal layer on the insulation film in which the connecting hole is formed, thereby covering an interior of the connecting hole and at least a part of an upper surface of the insulation film in a laminating direction thereof, and a metal layer removing step of polishing the upper surface of the insulation film on which the metal layer is deposited thereby removing the metal layer except for the interior of the connecting hole, an etch-back method performed on the embedded plug in at least an insulation film, and a chemical mechanical polishing method performed on the embedded plug in another insulation film.