A wiring substrate includes an insulation layer having an electronic component mounting area, and a wiring layer embedded in the insulation layer, the wiring layer having a first surface exposed from the insulation layer, to which a terminal of an electronic component is to be connected, a second surface opposite to the first surface, which is covered by the insulation layer, and a side surface. The second surface has a roughened surface and the side surface has a roughened surface, and a surface roughness of the second surface of the wiring layer is greater than a surface roughness of the side surface.