This book constitutes the refereed proceedings of the 4th International Workshop on Human Brain and Artificial Intelligence, HBAI 2024, held in Jeju Island, South Korea, on August 3, 2024. The 24 full papers and 5 short papers included in this book were carefully reviewed andselected from 74 submissions. They were organized in topical sections as follows: AI for brain science; AI for brain technology; and brain-inspired AI.