Disclosed in one embodiment according to the present disclosure is an electronic device comprising: a housing including a front surface, a rear surface facing the direction opposite to the front surface, and a side surface encompassing the space between the front surface and the rear surface; a display included in the housing and viewed on the outside of the electronic device through the front surface; an optical sensor which is positioned between the display and the rear surface to overlap at least one region of the display when viewed from above the front surface, and which includes a light-emitting part and a light-receiving part; and a first partition wall member positioned between the light-emitting part and the light-receiving part when the electronic device is in a first shape, and a second partition wall member that is present between the light-emitting part and the light-receiving part when the electronic device is in a second shape transformed from the first shape, wherein a straight line connecting the light-emitting part and the light-receiving part is perpendicular to the direction in which the electronic device changes from the first shape to the second shape. Other various embodiments identified through the specification are possible.