An electronic device comprising: a housing including a front plate facing a front surface and a rear plate facing a rear surface; a display assembly comprising a display visible through at least a part of the front plate; wherein the display assembly includes: an upper portion; a lower portion overlapping at least a partial area of the upper portion and including a first opening; and a flexible circuit board overlapping at least a partial area of the lower portion and including a second opening corresponding to at least a part of the first opening; a photosensor module including a sensing unit comprising a sensor corresponding to at least a part of the second opening and a plurality of pads disposed adjacent to the sensing unit and electrically coupled to the flexible circuit board; and an electrical component including circuitry or a mechanical structure (290, 291) disposed between the photosensor module and the rear plate and spaced apart from the photosensor module by a first distance (g), characterized in that, when viewed from above the front plate, the first opening is larger than the second opening in size, and wherein the photosensor module is disposed completely under the flexible circuit board and configured to detect at least a part of light passing through the first opening of the lower portion and the second opening of the flexible circuit board from the outside of the housing. a housing including a front plate facing a front surface and a rear plate facing a rear surface; a display assembly comprising a display visible through at least a part of the front plate; wherein the display assembly includes: an upper portion; a lower portion overlapping at least a partial area of the upper portion and including a first opening; and a flexible circuit board overlapping at least a partial area of the lower portion and including a second opening corresponding to at least a part of the first opening; a photosensor module including a sensing unit comprising a sensor corresponding to at least a part of the second opening and a plurality of pads disposed adjacent to the sensing unit and electrically coupled to the flexible circuit board; and an electrical component including circuitry or a mechanical structure (290, 291) disposed between the photosensor module and the rear plate and spaced apart from the photosensor module by a first distance (g), characterized in that, when viewed from above the front plate, the first opening is larger than the second opening in size, and wherein the photosensor module is disposed completely under the flexible circuit board and configured to detect at least a part of light passing through the first opening of the lower portion and the second opening of the flexible circuit board from the outside of the housing. an upper portion; a lower portion overlapping at least a partial area of the upper portion and including a first opening; and a flexible circuit board overlapping at least a partial area of the lower portion and including a second opening corresponding to at least a part of the first opening; a photosensor module including a sensing unit comprising a sensor corresponding to at least a part of the second opening and a plurality of pads disposed adjacent to the sensing unit and electrically coupled to the flexible circuit board; and an electrical component including circuitry or a mechanical structure (290, 291) disposed between the photosensor module and the rear plate and spaced apart from the photosensor module by a first distance (g), characterized in that, when viewed from above the front plate, the first opening is larger than the second opening in size, and wherein the photosensor module is disposed completely under the flexible circuit board and configured to detect at least a part of light passing through the first opening of the lower portion and the second opening of the flexible circuit board from the outside of the housing.