A signal transmission cable as a signal transmission component includes a laminate including a first thin portion on one of the opposite ends in a first direction and a second thin portion on the other end in the first direction. A portion between the first thin portion and the second thin portion in the laminate is a main line portion. The thickness of the first and second thin portions is thinner than the thickness of the main line portion. The surface on one end in the thickness direction of the laminate defined by the main line portion and the first and second thin portions is a continuous flat surface. A connector for external connection is arranged on the surfaces of the first and second thin portions, on the sides in which each of the thin portions and the main line portion have a difference in level.