A printed circuit board includes: a first substrate including a first cavity and first circuit units; and a second substrate disposed in the first cavity of the first substrate with an electronic component disposed therein, and including second circuit units having a higher density than the first circuit units, wherein the second substrate includes a first region and a second region, the first region of the second substrate includes an outermost circuit layer among the second circuit units, and circuit layers in the first region of the second substrate have a higher density than circuit layers in the second region of the second substrate.