The purpose of this paper is to search for a justifiable concept of autonomy that feasibly applies to bio-ethics and, based on this inquiry, suggest a practical model in a modern pluralist society. For this pur-pose, we classify personal autonomy into ‘metaphysical autonomy’ as the ideal theory guiding practical theories and both ‘narrow bioethical autonomy’ and ‘wide bioethical autonomy’ as non-ideal theories. We criticize narrow bioethical autonomy theories such as those posited by Tom Beauchamp and James Childress. Not only do they fail to flesh out metaphysical autonomy theories such as Harry Frankfurt`s, but they are not feasible because they ignore patient relationships and circumstances. We argue that Amartya Sen`s capability approach compliments the feminist concept of relational autonomy. Not only can this combination overcome the weaknesses found in narrow bioethical autonomy theories, but it allows for a practical framework to remove injustice and support autonomy. We call this combination ‘relational autonomy based on the capability approach’ and classify it as a theory of ‘wide bioethical au-tonomy.’ Based on this inquiry, we suggest a ‘plural forms model’ in a reasonable pluralism, which can reduce many of the autonomy-related conflicts. This model is useful in medical institution reform for explaining the plurality in both physicians` identities and cases of patients` autonomy (such as ambiva-lence) while it enhances patient autonomy through institutional and non-institutional reforms.