PROBLEM TO BE SOLVED: To provide a wiring board having a structure capable of allowing an adhesive to flow in easily, suppressing the formation of bubbles near the edge of an opening, and easily discharging the bubbles, when allowing the adhesive to flow into the opening of an insulation resin film provided on the main surface of the wiring board, to provide a packaging structure of electronic components, and to provide a semiconductor device.SOLUTION: In the wiring board 31, electronic components 32 are packaged while a surface with a plurality of external connection terminals 35 are faced down, and the electronic components 32 are stuck via an adhesive 42. In the wiring board 31, an insulation film 37 is formed on a surface where the electronic components 32 are packaged, an opening 38 is formed on the insulation film 37 so that a plurality of adjacent wiring patterns 34 having an electrode 36 to which an external connection terminal 35 of the electronic components 32 is connected are opened commonly and partially, and the end face of the opening 38 is formed obliquely to a direction where the wiring pattern 34 is extended at a point positioned at the center of the wiring board 31 in the outer-periphery part of the opening 38.
