A branch structure in which a branch harness is connected to a trunk harness includes connecting terminals. The trunk harness includes a plurality of trunk lines which are parallel-arranged. The branch harness includes a plurality of branch lines. The connecting terminals are respectively connected to the plurality of the trunk lines so as to electrically connect the plurality of the branch lines to the plurality of the trunk lines respectively. The trunk lines include connecting parts recessed in a radial direction. The connecting parts are arranged along an arrangement direction of the plurality of the trunk lines. The connecting terminals respectively includes connecting plate parts connected to the connecting parts in surface contact.