An electronic device includes the electronic element, the interposer substrate, on one surface of which the electronic element is mounted, and the interconnection substrate, on one surface of which the interposer substrate is mounted. One portion of the connection parts is an electrical connection part that electrically interconnects the interposer substrate and the interconnection substrate. The remaining portion is a dummy connection part that produces no functional deficiency even when the dummy connection part does not electrically interconnect the interposer substrate with the interconnection substrate. The dummy connection part includes at least one of the connection parts that at least partially overlap with the electronic element in a plan projection and are preferably arranged along an outer rim of the plan projection of the electronic element.