According to certain embodiments, an electronic device comprises a first housing; a second housing; a hinge disposed between the first housing and the second housing such that the second housing is foldable at one end of the first housing; and a flexible display disposed on a surface of the first housing and a surface of the second housing, wherein the flexible display comprises a display panel, and a glass layer disposed on the display panel, such that the display panel is between the glass layer and the surface of the first housing and the surface of the second housing, wherein the glass layer comprises: a bendable portion configured to be flat in an unfolded state when the first housing and the second housing are disposed horizontally adjacent, and to be bent in a folded state when the first housing and the second housing are vertically adjacent; and a first flat portion adjacent to the bending portion to form a boundary and a second flat portion disposed to extend from the first flat portion to an edge of the glass layer, wherein the glass layer comprises a glass member, wherein the glass member has a first thickness in the second flat portion, has a second thickness at the center of the bending portion, and has a third thickness less than the first thickness and greater than the second thickness in a section between the first flat portion and the center of the bending portion, and wherein the thickness of the glass member gradually decreases from the first flat portion to the center of the bending portion forming a concave portion.