In order to develop assistive robots which truly contribute to the QOL improvement, elaborate designs based on effectiveness analyses in human life are indispensable. We are developing a design framework utilizing ICF (International Classification of Functioning, Disability and Health), and planning to make a design support tool. Although the ICF provides a practical perspective and comprehensive vocabularies to analyze and describe human life, it has some problems in terms of systematicity and machine-readability. We are trying to reorganize the vocabulary of the ICF by ontology-engineering approach. We expect that the utility of the ICF in information systems is enhanced by this reorganization. We describe the concept of our attempt, and show its utility by case examples.