A branching structure for connecting a branch harness to a main line harness, includes connection terminals configured to electrically connect branch lines of the branch harness to main lines of the main line harness respectively, a terminal block on which the connection terminals are supported, and fasteners that respectively fasten the connection terminals onto the terminal block. Each of the connection terminals has a belt-shaped wound portion to be wound around a corresponding one of the main lines. The wound portion is fastened by a corresponding one of the fasteners so that both ends of the wound portion come closer to each other and a center portion of the wound portion tightens around the main line so as to be brought into surface contact with a bar conductor of the main line.