Abstract
This article illustrates the actual usage of the phrase koto ni naru in spoken language. In spoken language, I found that the usage which expresses "development of the fact" ,e.g. "I will have a headache tomorrow if I drink so much", is used most often. I also found certain characteristic relating to forms preceding and following koto ni naru. As for preceding constructions, toiu appears frequently, especially in the Diet records, which accounts for nearly 70%. This complex phrase toiu koto ni naru serves to emphasise the proposition and has the function of "onnecting". Also, after koto ni naru, wakeda occurs frequently, but depending on the place of occurrence, its function is also different. Specifically, when occurring at the end of a sentence, koto ni naru which can be considered to express a logical consequence, tends to co-occur with wakeda meaning "result", the entire phrase as a whole then having the meaning of "consequence". With koto ni naru wakeda ga appearing in the sentence, wakeda ga is irrespective of the meaning of koto ni naru -has the function of presenting facts.
