A printed wiring board includes a core substrate having a penetrating hole extending through the core substrate, an electronic component accommodated in the penetrating hole of the core substrate, a filler resin filling clearance between the component and the core substrate, a first resin insulation layer formed on the component and a first surface of the core substrate, and a second resin insulation layer formed on the component and a second surface of the core substrate on the opposite side of the first surface of the core substrate. The filler resin has elastic modulus which is set to be lower than 0.2 Gpa and thermal expansion coefficient which is set to be higher than 100 ppm and lower than 200 ppm, and the core substrate has elastic modulus which is set to be higher than 30 Gpa, and thermal expansion coefficient which is set to be lower than 10 ppm.