This paper aims a philosophical discussion on cross-cultural understanding in terms of education to light up the invisible problems concerning the topic, considering the reports of observations at some schools in Melbourne, Australia. This paper consists of three different parts: conceptual descriptions of the similar and more popular word "international education" ; reports of the case observations by the author at schools in Australia; a philosophical investigation of the depth of the problems of cross-cultural understanding and an outlook on the framework. From the philosophical discussion, 1) a complex characteristic of understanding as a dialogue, 2) foreign culture as the Other in a philosophical sense, and 3) cross-cultural understanding based on the continuation of mutuality as moral education, were pointed out in the framework of the problems.