This JIS standard specifies usability engineering processes for analyzing, specifying, developing, and evaluating safety-related human factors in medical devices, corresponding to IEC 62366-1:2015+Amendment 1:2020. The document establishes requirements for identifying and mitigating use errors that could result in harm to patients or operators, integrating human factors engineering into the device development lifecycle. Manufacturers must characterize the intended use environment, identify hazards associated with user interactions, develop mitigations through design and training, and conduct usability validation studies. The standard operates in conjunction with JIS T 14971 (risk management), as use-related risks must be identified and controlled through systematic usability engineering. The processes defined ensure that medical device designs accommodate user capabilities, limitations, and context of use to prevent foreseeable misuse. By systematically applying usability engineering principles, manufacturers reduce the likelihood of use errors and associated patient harm throughout the device lifecycle.