The purpose is to prevent the leakage of a electromagnetic noise from a wiring substrate. A wiring substrate (1) comprises a multilayered wiring layer, a structure (8) of a conductive material, and an electromagnetic wave absorber (5). In the wiring substrate (1), an electronic component (2), which is one example of an electromagnetic noise generation source, is mounted. The electronic component (2) has a high-frequency circuit. The structure (8) is formed using the multilayered wiring layer, and is so arranged that the structure (8) surrounds the electronic component (2) in a planar view and an opening (4) is formed in the surrounding part. The electromagnetic wave absorber (5) is so arranged as to cover the opening (4).