An embedded circuit board including a glass fiber layer, two dielectric layers, and two circuit layers is provided. The glass fiber layer has a first surface and a second surface corresponding to the first surface. The dielectric layers are disposed on the first surface and the second surface, respectively. The circuit layers are embedded in the dielectric layers above the first surface and the second surface, respectively. The outer surface of each circuit layer is coplanar with the outer surface of each dielectric layer, and a distance between the circuit layer and the glass fiber layer is greater than or equal to 3 μm. In addition, a process of the embedded circuit board is provided.