To elucidate the influence of nitrogen application rate on cool tolerance at the booting stage and respiratory activity of anther at the heading stage in the rice plants, the relationships among nitrogen content in the leaf blade and leaf sheath+culm at young microspore stage, cool tolerance at the booting stage and respiratory activity of anther at the heading stage were investigated for 3 rice cultivars-Yeomyungbyeo, Unbongbyeo and Milyang 23. Nitrogen content in the leaf blade at the young microspore stage was negatively correlated with respiratory rate of anther at the heading stage and fertility index, respectively. Respiratory activity of anther at the heading stage with 10ppm nitrogen application was higher than that of anther with 100ppm nitrogen application. On the Arrhenius plot of respiratory activity of anther at the heading stage, Yeomyungbyeo and Unbongbyeo showed a break at 18$^{circ}C$ and 18.5$^{circ}C$, respectively, with 100ppm nitrogen application, but did not show a break in respiratory activity of anther with 10ppm nitrogen application, while Milyang 23 showed a break at 20.5$^{circ}C$ and 21$^{circ}C$ with 10ppm and 100ppm nitrogen application, respectively. The highest correlation coefficient between fertility and respiratory rate of anther at the heading stage was shown at 20$^{circ}C$ in the temperature range of 15$^{circ}C$-30$^{circ}C$.