Recently, with the ourdoor air pollution, the indoor air pollution devided into living environment and working environment are raised as the problem of indoor space. Also, the more time lived in indoor space, the larger the influence of indoor air pollution. Therefore in this study, the spatial variation of ventilation efficiency was estimated through the experiment using a physical model. The experiment using a physical model. The experiment was conducted in two category; the central zone of ventilated air flow and the corner zone. As the result of experiment, high ventilation efficiency (90$sim$108%) was shown in the central zone of ventilated air flow. Whereas low ventilation efficiency (46$sim$77%) was shown in the corner zone. In conclusion, when the designing of ventilation was planned, the zone showed low ventilation efficiency should be considered.