Provided is an illumination device that includes a light emitting device having a first electrode and a second electrode and a mounting substrate including a first wiring pattern and a second wiring pattern. The first wiring pattern and the second wiring pattern face and are bonded to the first electrode and the second electrode, respectively, through a bonding material. The second electrode and the second wiring pattern are configured to be at least partially overlapped with each other in a plan view irrespective of an orientation of the light emitting device, under condition that the first electrode and the first wiring pattern are at least partially overlapped with each other in the plan view.