<p>In aerospace systems, separation devices are crucial in mission operations such as satellite deployment and stage separation. Pyrotechnic separation devices, which are conventionally used, can generate significant shock and debris, posing risks to structural integrity and sensitive equipment, particularly in small satellites and advanced launch vehicles. To address these challenges, this study proposes a nonexplosive ball-type pin puller utilizing a shape memory alloy (SMA) spring actuator. The developed device employs an SMA-driven actuator that releases a ball-lock mechanism to retract the pin and achieve separation without using explosives. An SMA spring was designed and validated through heating tests to confirm its capability of delivering the required displacement and force. The separation mechanism was optimized through dynamic analyses to ensure reliable ball release and pin retraction under various operational conditions. A prototype based on the optimized design was fabricated and experimentally tested, confirming the successful implementation of the intended separation function. Results demonstrate that the SMA-based ball-type pin puller provides a reliable, reusable, and low-shock alternative to conventional pyrotechnic separation devices, offering practical applicability for next-generation aerospace systems.</p>