The purpose of this paper is to consider instructional processes relating to a class in which the writing of argumentative essays was taught. The objects of the study were 80 students in the first grade of junior high school. When having students write argumentative essays, it is necessary to consider the setting of the subject, the processes of instruction, the composition of paragraphs, and a process of interactive evaluation. However, in the class in question, emphasis was placed on having the students employ a pattern of composition with assertions in the introductory and concluding paragraphs, and introducing a process of constructive criticism between pupils at the stage of choosing concrete examples to support opinions and the stage of deciding the structure of the essay. This process can be said to be effective for students who are writing argumentative essays for the first time, in that, for example, 100 percent of students used the paragraph composition models presented. On the other hand, insufficient emphasis was placed on ensuring that pupils accurately analyzed and understood the background problems to the subject, leading to a significant number of cases were seen where pupils wrote essays based on an inappropriate choice of examples. In terms of further study, in conjunction with making the intention behind the choice of subject more clear, a wide range of paragraph composition models can be developed.