Printed wiring board and method for manufacturing the same

A method for manufacturing a printed wiring board, comprising:

• preparing a core substrate having a first conductor pattern forming a first outei most layer of the core substrate and a second conductor pattern forming a second outermost layer of the core substrate on an opposite side with respect to the first conductor pattern;
• forming an opening portion in the core substrate;
• accommodating an electronic component in the opening portion formed in the core substrate;
• filling a filling resin into a space formed between the electronic component and an inner wall of the opening portion of the core substrate;
• and
• forming a plurality of resin insulating layers on a first surface and a second surface of the core substrate, respectively,
• wherein the filling of the filling resin includes foifuing a resin layer comprising the filling resin on the second conductor pattern of the core substrate such that the filling resin fills spaces formed in the second conductor pattern, and polishing the resin layer such that the second conductor pattern is exposed, and the forming of the resin insulating layers includes forming one of the resin insulating layers on the second surface of the core substrate after the resin layer is polished.