To enhance the functionality of a constant-torque flexure hinge (CTFH), a bidirectional double-arc constant-torque flexure hinge (BD-CTFH) is proposed. The BD-CTFH exhibits characteristics such as a bidirectional constant-torque output and sufficient proportion of constant-torque output. The primary objective of this study is to establish a pseudo-rigid-body model of the BD-CTFH (BD-PRBM) to accurately determine the constant-torque output performance. In addition, a comprehensive analysis of the torque-angle characteristics of the BD-CTFH is conducted through finite element analysis (FEA), theoretical calculations, and experimental testing. The results indicate that the discrepancy between the theoretical and FEA results is within 2 %, confirming the accuracy of the BD-PRBM. Moreover, the average deviation between the experimental and theoretical results is within 5 %, further validating its accuracy. Finally, through preloading tests, it is verified that the BD-CTFH exhibits a constant-torque region of 12–36° (and -12–-36°).