A printed wiring board suppresses characteristic impedance mismatch that occurs when the printed wiring board is equipped with a through-type coaxial connector, and includes ground layers stacked in a plurality of layers via insulating layers; a through-hole; a clearance serving as an anti-pad provided in an area between the through-hole and the ground layers; and signal wiring extending from the through-hole to between prescribed ones of the ground layers through the clearance. The prescribed ones of the ground layers have a wiring-impedance adjustment area for adjusting the impedance of the signal wiring, the wiring-impedance adjustment area being arranged so as to overlap a portion of the signal wiring in the clearance.