Abstract: A component built-in module of the present invention includes: a flexible substrate that includes a first surface and a second surface on an opposite side of the first surface, the first surface including a concave part recessed in a direction from the first surface toward the second surface; a plurality of electronic components that are mounted on the first surface, mounting heights of the electronic components from the first surface to respective upper surfaces of the electronic components differing from each other; and a resin that seals the first surface. Among the plurality of electronic components, at least an electronic component having a highest mounting height is mounted in the concave part.