The invention discloses a watch step-counting accuracy detection device capable of automatically leveling. The device comprises a driving motor, a mechanical counter, a vibration-reducing bottom column, a power indicator, a liquid crystal display, a speed control button, an emergency stop button, a device switching button, a control panel, non-slip supporting legs, a power connector, a detection device main body, a watch swing arm and a swing arm braking apparatus. The watch step-counting accuracy detection device disclosed by the invention is provided with the swing arm braking apparatus, during use of the watch step-counting accuracy detection device, after the driving motor is powered off to stop working, the watch swing arm simultaneously stops swinging, and the condition that the detection result is different from the accuracy value because the watch swing arm continuously swings due to inertia is avoided. According to the vibration-reducing bottom column arranged below the detection device main body, the device can be automatically adjusted to enable the detection device main body to be located in a horizontal state, and the detection result accuracy of the watch step-counting accuracy detection device is effectively improved.