A through-hole layout structure is suitable for a circuit board. The through-hole layout structure includes a pair of first differential through-holes, a pair of second differential through-holes, a first ground through-hole, a second ground through-hole, and a third ground through-hole, which are all arranged on a first line.The first ground through-hole is located between the pair of first differential through-holes and the pair of second differential through-holes. The pair of first differential through-holes is located between the first ground through-hole and the second ground through-hole. The pair of second differential through-holes is located between the first ground through-hole and the third ground through-hole.