CASE FOR ELECTRONIC DEVICE

A portable electronic device includes:a front cover, a display exposed through the front cover, a rear cover,a case comprising a first side portion and a second side portion, anda processor operatively coupled to the display;the first side portion including:at least one hole area defining a through-hole passing through the first side portion, the through-hole having a metallic curved inner surface,a bonding layer, disposed on the metallic curved inner surface, and including an organic material and an oxidation layer of the metallic material, andan insulation member formed, by injection molding of a polymer resin, on the bonding layer such that a substantial portion of the hole area remains open,a first metallic portion including a metallic material and electrically connected with a communication circuit of the device and configured to be used as an antenna;the second side portion including a second metallic portion, including the metallic material and spaced apart from the first metallic portion by a first gap;the case further comprising a first bonding insulation layer disposed between the first metallic portion and the second metallic portion and including a first part, a second part, and a third part:the first part of the first bonding insulation layer including a first insulation member located in the first gap;the second part of the first bonding insulation layer including a first bonding layer in contact with the first metallic portion and the first insulation member, the first bonding layer including an organic material; andthe third part of the first bonding insulation layer including a second bonding layer in contact with the first insulation member and the second metallic portion.