Wiring board and electronic component device

A wiring board includes a wiring forming region in which a plurality of wiring layers are stacked while sandwiching insulating layers, an outer periphery region which is arranged around the wiring forming region and in which a reinforcing pattern is formed in the same layer as each of the wiring layers. An area ratio of the reinforcing pattern to the outer periphery region and an area ratio of the wiring layer to the wiring forming region are substantially the same in each of the layers, and the reinforcing patterns exist without a gap in the outer periphery region when the wiring board is viewed in planar perspective.