A signal line is a linear conductor provided within a laminated body. A first ground conductor is provided on a positive direction side in a z axis direction within the laminated body, compared with the signal line, and overlaps with the signal line in a planar view seen from the z axis direction. A second ground conductor is provided on a negative direction side in the z axis direction within the laminated body, compared with the signal line, and overlaps with the signal line in the planar view seen from the z axis direction. Via hole conductors connect the ground conductors to each other. In the first ground conductor, a plurality of opening portions are arranged along the signal line in the planar view seen from the z axis direction. The via hole conductors are provided between the opening portions adjacent to one another, in an x axis direction.