According to an embodiment, an electronic device (e.g., the electronic device 100 of FIGS. 1 to 3) comprises a first structure (e.g., the first structure 101 of FIGS. 1 to 3) including a first plate (e.g., the first plate 111a of FIGS. 1 to 3) providing a first surface (e.g., the first surface F1 of FIG. 3 or 4) and a second surface (e.g., the second surface F2 of FIG. 8) facing away from the first surface, a second structure (e.g., the second structure 102 of FIGS. 1 to 3) coupled to surround at least a portion of the first structure and guiding a sliding of the first structure in a direction parallel with the first surface or the second surface of the first structure, a roller (e.g., the roller 151 of FIG. 3) rotatably mounted on an edge of the second structure, a flexible display (e.g., the display 103 of FIGS. 1 to 3) including a first area (e.g., the first area A1 of FIG. 3) mounted on the first surface of the first structure and a second area (e.g., the second area A2 of FIG. 3) extending from the first area, the second area of the flexible display guided at least partially by the roller to be inserted or received from a side of the second structure to an inside of the second structure or exposed to an outside of the second structure as the first structure is slid, and at least one support sheet (e.g., the support sheet 153 of FIG. 3) mounted on the roller and selectively wound around the roller as the roller rotates, wherein the support sheet is wound around the roller when the second area is received inside the second structure, and is unfolded inside (e.g., the rear surface of the second area) the second area when the second area is exposed to the outside of the second structure.
