The effects of red light on the $\alpha$-amylase activity of barley during germination was studied. The $\alpha$-amylase activity was highest at 5th day on germination, showing rapid increase from the 3rd-day of germination. The highest activity of $\alpha$-amylase was shown among the groups treated by red light at 100 Lux luminous intensity for 3 hours a day. The $\alpha$-amylase activity of barley during germination under the red light increased to 44% compared with that of barley during germination under the dark. The protein content was not increased by red light.