PURPOSE: To provide a substrate which enables easy and reliable mount of a semiconductor device wherein an outer lead is made straight and cut short and a package structure thereof.

CONSTITUTION: A recessed part 11 is formed in a region which is relevant to a package 4 to be mounted and a wiring pattern 12 is formed on a surface corresponding to a lead 3 of the package. A lead of a semiconductor device is straightened and connected onto each wiring pattern. A first substrate 1 having a through-hole in a region relevant to a package and a wiring pattern on a surface, a second substrate having a wiring pattern on a front and a rear and a third substrate having a through-hole in a region relevant to a package and a wiring pattern on a surface are laminated one by one. Wiring patterns of the first, second and third substrates are connected each other through through-holes and a multi-layer wiring structure is constituted.