As a novel traction and load-bearing component derived from steel wire ropes, the elevator belt has been widely applied in modern elevator systems due to its flexibility, corrosion resistance, and high transmission efficiency. However, long-term cyclic stresses can induce hidden defects such as cord wear, broken wires, and strand fractures, which are difficult to detect in time and pose serious safety risks. Existing methods often suffer from slow response, low efficiency, or dependence on shutdown inspection, making them unsuitable for online detection of broken wires. To overcome these limitations, this study proposes an eddy current-based detection method for broken wires in elevator belt steel cords. A segmented mutual-inductance probe with a spatially wound, openable configuration was designed, and finite element simulations were conducted to optimize coil turns and lift-off parameters. Based on the optimized design, a prototype was fabricated and a test platform established. Sensitivity was first evaluated by introducing different numbers of broken wires into a single steel strand, followed by detection experiments on elevator belts. Results show that the probe can stably detect at least four broken wires at a belt speed of 0.5 m/s. The induced signal amplitude increases with the number of broken wires, and the system exhibits good dynamic detection capability. These findings provide a practical reference for online detection of broken wires in elevator belt steel cords and offer technical support for enhancing elevator safety and enabling preventive maintenance.