An electronic device mounting substrate includes: a first wiring substrate shaped in a rectangular frame, an interior of the rectangular frame constituting a first through hole; a second wiring substrate shaped in a rectangular frame or plate, the second wiring substrate being disposed so as to overlie a lower surface of the first wiring substrate and be electrically connected to the first wiring substrate; a metallic plate disposed so as to overlie a lower surface of the second wiring substrate so that the second wiring substrate is sandwiched between the metallic plate and the first wiring substrate; and a lens holder secured to an outer periphery of the metallic plate. A frame interior of the first wiring substrate, or a frame interior of each of the first wiring substrate and the second wiring substrate, constitutes an electronic device mounting space.