The present invention relates to a hub structure for constructing a curtain wall that can be applied to construction of regular or irregular curtain walls when a building or a structure is constructed by a curtain wall method. The hub structure includes a hub which has a structure of a polygonal cross-section and tap holes on the circumferential surface thereof; a hollow frame member connected to the circumferential surface of the hub to support an outer wall panel for the curtain wall; a bracket engaged to a front end of the frame member facing the circumferential surface of the hub and formed with a bolt insertion hole in line with the tap hole of the hub; a bolt fastened to the tap hole of the hub to engage the frame member to the circumferential surface of the hub after the bracket is engaged to the frame member in the state the bolt is inserted in the bolt insertion hole of the bracket; a nut fastened to the bolt when the frame member is engaged to the circumferential surface of the hub and formed with a slot positioned between the circumferential surface of the hub and the bracket in line with the tap hole of the hub and the bolt insertion hole of the bracket; and an operation pin attached to the circumferential surface of the bolt through the slot of the nut in the state in which the bolt is engaged to the bracket and the nut, and rotated in order for the bolt to be fastened to the tap hole of the hub while the bracket is engaged to the front end of the frame member.
