A printed circuit board comprising: a core insulating layer including a first via hole; a first conductive via filling the first via hole formed through the core insulating layer; a first insulating layer on an upper portion or a lower portion of the core insulating layer, the first insulating layer including a first circuit pattern groove and a first expansion part groove; a first circuit pattern filling the first circuit pattern groove of the first insulating layer; a first conductive expansion part filling the first expansion part groove of the first insulating layer and extending from the first conductive via; a second insulating layer covering the first circuit pattern, a second via hole, and a second conductive via filling the second via hole formed through the second insulating layer; a third insulating layer, including a second circuit pattern groove and a second expansion part groove, being on the second insulating layer; a second circuit pattern filling the second circuit pattern groove of the third insulating layer; a second conductive expansion part filling the second expansion part groove of the third insulating layer and extending from the second conductive via;, wherein the first insulating layer has a same thickness as that of the first circuit pattern, wherein the second insulating layer has a same thickness as that of the second conductive via, wherein the third insulating layer has a same thickness as that of the second circuit pattern, wherein the first insulating layer comprises a same material as a material of the third insulating layer, wherein the core insulating layer comprises a same material as a material of the second insulating layer, wherein each of the first and third insulating layers (120, 133) includes a first resin material into which a glass fiber is not impregnated and a filler distributed in the first resin material, wherein each of the core and second insulating layers (110, 130) includes a second resin material (11 0b, 130b) into which the glass fiber(110a, 130a) is impregnated and a filler (110c, 130c) distributed in the second resin material, wherein the first circuit pattern has a same thickness as that of the first conductive expansion part, and wherein the second circuit pattern has a same thickness as that of the second conductive expansion part. a core insulating layer including a first via hole; a first conductive via filling the first via hole formed through the core insulating layer; a first insulating layer on an upper portion or a lower portion of the core insulating layer, the first insulating layer including a first circuit pattern groove and a first expansion part groove; a first circuit pattern filling the first circuit pattern groove of the first insulating layer; a first conductive expansion part filling the first expansion part groove of the first insulating layer and extending from the first conductive via; a second insulating layer covering the first circuit pattern, a second via hole, and a second conductive via filling the second via hole formed through the second insulating layer; a third insulating layer, including a second circuit pattern groove and a second expansion part groove, being on the second insulating layer; a second circuit pattern filling the second circuit pattern groove of the third insulating layer; a second conductive expansion part filling the second expansion part groove of the third insulating layer and extending from the second conductive via;, wherein the first insulating layer has a same thickness as that of the first circuit pattern, wherein the second insulating layer has a same thickness as that of the second conductive via, wherein the third insulating layer has a same thickness as that of the second circuit pattern, wherein the first insulating layer comprises a same material as a material of the third insulating layer, wherein the core insulating layer comprises a same material as a material of the second insulating layer, wherein each of the first and third insulating layers (120, 133) includes a first resin material into which a glass fiber is not impregnated and a filler distributed in the first resin material, wherein each of the core and second insulating layers (110, 130) includes a second resin material (11 0b, 130b) into which the glass fiber(110a, 130a) is impregnated and a filler (110c, 130c) distributed in the second resin material, wherein the first circuit pattern has a same thickness as that of the first conductive expansion part, and wherein the second circuit pattern has a same thickness as that of the second conductive expansion part.