The purpose of this paper is to give consideration to the professional expertise of headteachers as reflective practitioners by assessing the Michael Eraut's criticism of Donald Schön. The number of reflective teacher education programmes have been increasing in the last two decades and reflective headteacher education programmes have been gained attention in these years. However, there seems to be several ways of thinking of professional expertise of headteachers as reflective practitioners. M.Eraut is the one who is influenced by Argyris & Schön's idea, double-loop learning, and envisages professional education based on reflective practitioners. However, he criticizes Schön's idea, 'reflection' and provides his original point of view. The points of Eraut's criticisms and a suggestion are as follows: 1. Schön's idea of reflection is problematic. The difference between reflection-in-action and reflection-on-action is not clear. His interest is not so much reflection-in and on-action as 'reflection-for-action'. 2. Schön does not regard for the effect of time scale to the form of reflection. 3. The deliberate meta-process should be focused on the most in professional education. Next, I gave examination against these Eraut's criticisms. The points are as follows: 1. Reflection-in-action is core of artistry of professional practice in the uncertainty. 2. The difference between two types of reflection comes not from time scale but from 'present-action'. 3. The importance of 'Reflection on reflection-in-action'. Finally, based on the comparison of Eraut and Schön, the way of education for headteachers should be is suggested: the importance of designing "reflective practicum" in the curriculum, which is characterized by "learning by doing" and "coaching". It helps to bridge the academic world and the practice world.