A flexible wiring board includes a signal line and a conductive portion that overlaps the signal line in plan view. The conductive portion includes a first line portion extending in a first direction and having a first part and a second part, a second line portion extending in a second direction and having a third part and a fourth part, and a third line portion. The third line portion has a line width smaller than a line width of the first part and a line width of the second part, is connected to the first and second parts, and is provided between the first part and the second part. The conductive portion includes a fourth line portion that is connected to the third part and the fourth part and that is provided between the third part and the fourth part. The third line portion and the fourth line portion intersect.