WIRING BOARD

PROBLEM TO BE SOLVED: To provide a wiring board which is capable of preventing cracks from occurring in a boundary between the main body and the periphery of a via conductor, even when the center axes of a viahole and a through-hole are set coincident with each other and an inner diameter difference between the through-hole and the viahole is set small. SOLUTION: The wiring board 100 is equipped with the through-hole 111, the first viahole 121, and the second viahole 131. Their center axes are coincident with each other. Provided that the inner diameters of the through-hole 111 and the first and the second viahole 121 and 131 are represented by D1 and D2 respectively, an inner diameter difference between the through-hole 111 and the viaholes 121 and 131 is represented by a formula, (D1-D2). The inner diameter difference (D1-D2) is set at 170 μm or below, and a first resin insulating layer 120 and a second resin insulating layer 130 each have a thermal expansion coefficient of 60 ppm or below. COPYRIGHT: (C)2004,JPO