Conventional research on linear polarization photodetector for 2D materials has focused on the search for different anisotropic materials, combinations between materials, introducing plasmonic structures, and patterning 2D materials to improve performance. However, these methods provide limited improvement in polarization sensitivity. Here, a balanced photodetector structure is proposed that does not require an additional process and relies only on the presence of anisotropy in the material itself to substantially improve the polarization sensitivity. The balanced photodetector consists of two ReS2 photodetectors, where the single ReS2 photodetector exhibits excellent performance at 650 nm illumination, including a responsivity and detectivity of 0.28 A W−1 and 4.22 × 109 Jones. Benefiting from the anisotropy of ReS2, the single photodetector achieves excellent polarization sensitivity of 2.79 at 650 nm. The balanced photodetector system achieves an excellent performance of ≈20 dB linear polarization extinction ratio and 0.003° Hz−1/2 noise equivalent light polarization difference at 100 kHz. These performances can also be further optimized by adjusting the gate voltage. The results provide a basis for further development of high‐performance polarization photodetector for 2D materials.