A programmable semiconductor device has a switch element in an interconnection layer, wherein in at least one of the inside of a via, interconnecting a wire of a first interconnection layer and a wire of a second interconnection layer, a contact part of the via with the wire of the first interconnection layer and a contact part of the via with the wire of the second interconnection layer, there is provided a variable electrical conductivity member, such as a member of an electrolyte material. The via is used as a variable electrical conductivity type switch element or as a variable resistance device having a contact part with the wire of the first interconnection layer as a first terminal and having a contact part with the wire of the second interconnection layer as a second terminal.