The changes in air temperatures on Mount (Mt.) Fuji, Japan were evaluated. Various parameters of air temperatures on Mt Fuji in Japan were obtained from Japan Metrological Agency. Parameters of air temperatures were positively correlated with years on Mt. Fuji. In addition, the number of days under –24°C in January was negatively correlated with years. Global warming was also proved on Mt. Fuji in Japan, especially in winter. Therefore, we need to deal with global warming effect.