In this paper, a model of design information that can take into account various information such as that of the environment around a designer and the past experiences is proposed. The authors believe that design models based on a framework of problem solving do not explicitly describe all design activities. In order to compensate for this insufficiency, the authors propose the concept of a gazing point in the design situation which is clarified by the designer's explanation of his/her problem-solving processes. The gazing point controlling process is the design activities that play a role in extracting the designer's unique information from all the information that the designer can recognize in a design. The method of design experiments that consist of two sessions (design session and explanation session) is proposed and the experiment is carried out. Besides the design session, which is the same as in the past standard experiments, in the explanation session, the authors acquire an explanation of design activities, which was recorded in the design session, by means of questions and answers while showing the designer the design process on video. The results confirm the validity of the concept of the gazing point in the design situation.