A wiring board of the present invention is equipped with a laminated waveguide as a high-frequency signal transmission line. The laminated waveguide is composed of a dielectric substrate, a pair of main conductive layers laminated on the upper surface and the lower surface of the dielectric substrate, a plurality of via-holes extending in a thickness direction in the dielectric substrate so that they electrically connect the pair of the main conductive layers, and a sub-conductive layer provided in the dielectric substrate so that it is parallel to the main conductive layers and is electrically connected to the via-holes, the plurality of the via-holes form two rows extending in a signal transmitting direction with a mutual distance from each other, and in each row, the distance between adjacent via-holes is adjusted to less than 1/2 of a signal wavelength, a region surrounded with the pair of the main conductive layers and the two rows of the via-holes forms a signal transmitting region, and on both sides in the outside of the signal transmitting region, the sub-conductive layer is provided. The transmittting line by the laminated waveguide which is formed in this wiring board has especially excellent transmitting characteristics of high-frequency signals. In addition, since this wiring board can be easily produced by a laminating technology of ceramics, this wiring board also has excellent productivity.