A method for manufacturing a printed wiring board includes preparing a core substrate having first and second surfaces, forming a penetrating hole from the first surface toward the second surface of the substrate, forming first conductor on the first surface of the substrate, forming second conductor on the second surface of the substrate, and filling conductive material in the hole such that through-hole conductor connecting the first and second conductors is formed. The forming of the hole includes forming a first opening portion on the first-surface side of the substrate, a second opening portion from the bottom of the first portion toward the second surface, and a third opening portion from the bottom of the second portion toward the second surface, and the forming of the hole satisfies X2