The current distributions within a power transmission cable composed of helically woundlong tape superconductors have been studied by solving the circuit equation with theinductance matrix among divided segments within a tape conductor under the Bean model.The self- and mutual inductances of helical thin tape conductors are calculated from theanalytical expressions in the form of an infinite series. In addition, it is shown thatthe distinction between the right-handed and left-handed helixes is generallynecessary in the mutual inductance between two long coaxial helical conductors.