The electronic device 220 may be operated such that, in the unfolded state, the first surface 231 of the first housing 230 and the third surface 241 of the second housing 240 face substantially the same direction, i.e., the first direction (+z axis direction) and in the folded state, the first surface 231 and the third surface 241 face opposite directions. The electronic device 220 may be operated such that, in the unfolded state, the second surface 232 of the first housing 230 and the fourth surface 242 of the second housing 240 face substantially the same direction, i.e., the second direction (?z axis direction) and in the folded state, the second surface 232 and the fourth surface 242 face each other.
The first housing 230 includes a first side frame 233 forming at least a portion of the exterior of the electronic device 220 and a first rear cover 234 coupled to the first side frame 233 and forming at least a portion of the second surface 232 of the electronic device 220. The first side frame 233 includes a first side surface 233a, a second side surface 233b extending from one end of the first side surface 233a, and a third side face 233c extending from the other end of the first side surface 233a. The first side frame 233 may be formed in a rectangular (e.g., square or rectangular) shape through the first side 233a, the second side 233b, and the third side 233c.