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 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 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 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 . <EOS>