To minimize thermal influence when integrally forming the sealing member on a flexible wiring board, a sealing structure includes a housing, a flexible wiring board inserted therethrough, and a sealing member integrally formed with the flexible wiring board to airtightly seal a gap between the housing and the flexible wiring board, the flexible wiring board includes a base substrate made of an elastic material, an electrically conductive printed wiring layer formed on a surface of the base substrate, and a cover film covering a surface of the printed wiring layer, and the printed wiring layer which crosses the sealing member is formed as a plurality of divided print wiring layers at only a crossing region with the sealing member and its vicinity.