Abstract: In recent years, quantum computing has attracted worldwide attention, however the hardware is still in its infancy and there are many challenges that must be overcome to surpass conventional technologies. To address these challenges, the software that can effectively utilize the quantum hardware plays a crucial role. In terms of the software, it is useful to apply the wealth of knowledge in the field of classical computing, and we have been working on the practical application by the hybrid quantum-classical algorithm. In this talk, we will dive into the synergy of quantum and classical computing and introduce applications of their hybrid use. We will also talk what kind of research is needed to further accelerate the development of quantum computing and to realize symbiosis between quantum and classical computing technologies.