An electronic device comprising: a front window forming at least part of a front surface of the electronic device (200, 300), the front window comprising a first planar portion, a first bent portion, and a second bent portion, the first and second bent portions (3402, 3403) bent in opposite directions from the first planar portion; a rear surface comprising a second planar portion, a third bent portion, and a fourth bent portion, the third and fourth bent portions (2152, 2153) bent in opposite directions from the second planar portion; a flexible display module comprising a planar display portion visible via the first planar portion of the front window, a first bent display portion visible via the first bent portion of the front window, and a second bent display portion visible via the second bent portion of the front window; and a metal housing disposed along the outer periphery of the electronic device (200, 300), the metal housing comprising a first side portion and a second side portion opposite the first side portion, an upper portion and a lower portion opposite the upper portion, the first and second side portions (221, 22) having a first height, and the upper and lower portions (223, 224) having a second height greater than the first height; characterised in that, in a corner where the first side portion and the upper portion are interconnected, and in a corner where the first side portion and the lower portion are interconnected, the height of the first side portion gradually increases at both front portion adjoined with the first bent portion and rear portion adjoint with the third bent portion from the first height to the second height, wherein the first, second, third and fourth bent portions (2152, 3402, 2153, 3403) are configured as a part of the side surfaces of the electronic device (200, 300) together with the first and second side portions of the metal housing (221, 222), respectively. a rear surface comprising a second planar portion, a third bent portion, and a fourth bent portion, the third and fourth bent portions (2152, 2153) bent in opposite directions from the second planar portion; a flexible display module comprising a planar display portion visible via the first planar portion of the front window, a first bent display portion visible via the first bent portion of the front window, and a second bent display portion visible via the second bent portion of the front window; and a metal housing disposed along the outer periphery of the electronic device (200, 300), the metal housing comprising a first side portion and a second side portion opposite the first side portion, an upper portion and a lower portion opposite the upper portion, the first and second side portions (221, 22) having a first height, and the upper and lower portions (223, 224) having a second height greater than the first height; characterised in that, in a corner where the first side portion and the upper portion are interconnected, and in a corner where the first side portion and the lower portion are interconnected, the height of the first side portion gradually increases at both front portion adjoined with the first bent portion and rear portion adjoint with the third bent portion from the first height to the second height, wherein the first, second, third and fourth bent portions (2152, 3402, 2153, 3403) are configured as a part of the side surfaces of the electronic device (200, 300) together with the first and second side portions of the metal housing (221, 222), respectively.