A switch device according to an embodiment of the technology includes a first electrode, a second electrode that is disposed to face the first electrode, and a switch layer that is provided between the first electrode and the second electrode. The switch layer contains a chalcogen element. The switch layer includes a first region and a second region which have different composition ratios of one or more of chalcogen elements or different types of the one or more of chalcogen elements. The first region is provided close to the first electrode. The second region is provided closer to the second electrode than the first region.