One solution for the labor shortage problem in a health care domain is to improve the work efficiency by a business process re-engineering project. For a sustainable operation of the improved work, a co-creation with care workers is effective. However, they are too busy due to a lot of daily tasks to cooperate with the co-creation project as well as they are not interested in it. This paper analyzes their psychological burden to join the project with a focus on a closed-mind which is a characteristics of care workers and discusses on how to eliminate the mind.