Optimization of the helically-winding structure required for the helical fusion reactor utilizing the high temperature superconductor (HTS) tape is studied by numerical calculation. When the HTS tapes are wound to be the helical structure without the torsion, a significant edgewise strain appears. This might lead to the degradation of the performance of the HTS tape. Therefore, the edgewise strain must be minimized. It is found that the edgewise strain can be suppressed by the proper determination of the torsion by the optimization utilizing the Fourier decomposition of the distribution of the edgewise strain. The HTS tapes with edgewise strain are intrinsically deformed due to the torsion to reduce the edgewise strain so to be an “edgewise-strain-free” helical shape.