“The environment” is a familiar word. However, the exact meaning of the word is ambiguous and inconsistence. Hence, this study aim to clarify the meaning of “the environment” qualitatively and quantitatively, by investigating and analyzing sixty-seven textbooks of the environment. As a result, main elements of “the environment” are listed by the extraction of the textbook contents and divided into eleven fields. In addition, the proportion of each field varies among the textbooks and is visualized by boxplot with all of the textbooks, indicating that “pollution” and “climate system” are large proportion. These results help us to understand “the environment” and to develop the environmental studies.