A package substrate includes: a first conductive layer having plural first terminal pattern portions connected to a semiconductor part loaded on a first principal surface through plural first external connection conductors, which is formed on the first principal surface; a second conductive layer having plural second terminal patterns connected to a system substrate mounted on a second principal surface opposite to the first principal surface through a second external connection conductor, which is formed on the second principal surface; an intermediate conductive layer formed between the first conductive layer and the second conductive layer; interlayer insulating layers formed between the first conductive layer and the intermediate conductive layer as well as between the second conductive layer and the intermediate conductive layer; and plural interlayer connection conductors stacked for connecting between the first conductive layer and the second conductive layer so as to pierce through the interlayer insulating layers.