Disclosed herein is a branch connecting structure for a hoistway cable. The structure includes a hoistway cable having a plurality of communication wires in a sheath. A branch cable connects each communication wire to a hall button or an indicator. A terminal block covers a first surface of the hoistway cable, and includes wire terminal members integrally having an input terminal and an output terminal. A branch block covers a first surface of the branch cable, and includes branch terminal members integrally having an input terminal and an output terminal. A first support block covers a second surface of the hoistway cable, and is compressed against the terminal block to be coupled thereto. A second support block covers a second surface of the branch cable, and is compressed against the branch block to be coupled thereto. A cover covers outer circumferences of the terminal block and the branch block.