A semiconductor device 100 has such a structure that a semiconductor chip 110 is flip-chip mounted on a wiring board 120. The wiring board 120 has a multilayer structure in which a plurality of wiring layers and a plurality of insulating layers are arranged, and has a structure in which insulating layers of a first layer 122, a second layer 124, a third layer 126 and a fourth layer 128 are provided. The first layer 122 has a first insulating layer 121 and a second insulating layer 123. A protruded portion 132 which is protruded in a radial direction (a circumferential direction) from an outer periphery at one surface side of a first electrode pad 130 is formed on a whole periphery over a boundary surface between the first insulating layer 121 and the second insulating layer 123.