To address the gaps in the literature, in this study, we present the first example of a thermal engine based on elastic crystals. When the crystal is loaded with a weight and placed between high (34-37 °C)-and low (~0 °C)-temperature heat sources, it continuously oscillates, indicating that it can extract kinetic energy from the heat sources. The oscillations continued for at least 160 h, corresponding to over 3.9 million cycles of bending and stretching, demonstrating the high durability of the elastic crystal. To the best of our knowledge, this study is the first to report the continuous operation of an organic crystal-based thermal engine under only static temperature differences. Our results highlight the potential applications of organic elastic crystals as actuators owing to their high-speed responsiveness to external fields and remarkable durability.