Shortly after the Russian invasion of Ukraine in February 2022, Prime Minister Fumio Kishida announced that Japan would accept Ukrainians who had fled to third countries. While this prompt decision should be welcomed, the Japanese government has been criticised for its reluctance to accept refugees for years. Because of Japan's past restrictive approach to refugees and asylum-seekers, the decision to accept Ukrainians was met with surprise. Why, then, did the Japanese government decide to accept Ukrainians? This article explores the rationale behind this decision by analysing the language used by Cabinet members of the Japanese government in Diet discussions from the perspective of Critical Discourse Analysis, which sees language as a form of social practice. By adopting the concept of "ontological security", or the security of self-identity, it argues that, while Japan's decision to accept Ukrainians was prompted by its pursuit of ontological security derived from its international relations, its pursuit of ontological security rooted in its biographical narrative caused a desire to prevent this case from affecting Japan's future refugee policy and to minimise the acceptance of refugees in the country.