An electronic device, comprising: a first housing including a first support member; a second housing foldably coupled to the first housing through a hinge mechanism and including a second support member; a flexible display supported by the first housing and the second housing, the flexible display including: a window layer, a display panel disposed under the window layer, and a bending portion extended from the display panel and attached to a rear surface of the display panel, the bending portion including: an extension portion extending outside the display panel and including a control circuit, and a flexible substrate electrically connected to the extension portion; a cover tape extending from at least some of the flexible substrate to at least some of the extension portion; an adhesive member disposed between the cover tape and the extension portion; a first waterproof member disposed between the display panel and the second support member to substantially surround the bending portion; a second waterproof member disposed between the cover tape and the second support member, the first waterproof member and the second waterproof member being spaced apart; and a third waterproof member that connects one end of the first waterproof member and one end of the second waterproof member, and connects another end of the first waterproof member and another end of the second waterproof member, wherein when the flexible display is viewed from above, the control circuit (4311, 4321a) and the flexible substrate overlap a first waterproof space formed through the first waterproof member, the second waterproof member, and the third waterproof member, and wherein the control circuit is disposed between the flexible substrate and the adhesive member, the control circuit being sealed by the adhesive member and the cover tape. a first housing including a first support member; a second housing foldably coupled to the first housing through a hinge mechanism and including a second support member; a flexible display supported by the first housing and the second housing, the flexible display including: a window layer, a display panel disposed under the window layer, and a bending portion extended from the display panel and attached to a rear surface of the display panel, the bending portion including: an extension portion extending outside the display panel and including a control circuit, and a flexible substrate electrically connected to the extension portion; a window layer, a display panel disposed under the window layer, and a bending portion extended from the display panel and attached to a rear surface of the display panel, the bending portion including: an extension portion extending outside the display panel and including a control circuit, and a flexible substrate electrically connected to the extension portion; an extension portion extending outside the display panel and including a control circuit, and a flexible substrate electrically connected to the extension portion; a cover tape extending from at least some of the flexible substrate to at least some of the extension portion; an adhesive member disposed between the cover tape and the extension portion; a first waterproof member disposed between the display panel and the second support member to substantially surround the bending portion; a second waterproof member disposed between the cover tape and the second support member, the first waterproof member and the second waterproof member being spaced apart; and a third waterproof member that connects one end of the first waterproof member and one end of the second waterproof member, and connects another end of the first waterproof member and another end of the second waterproof member, wherein when the flexible display is viewed from above, the control circuit (4311, 4321a) and the flexible substrate overlap a first waterproof space formed through the first waterproof member, the second waterproof member, and the third waterproof member, and wherein the control circuit is disposed between the flexible substrate and the adhesive member, the control circuit being sealed by the adhesive member and the cover tape.