In 1943 Akabori, Shimazu and Nakanishi (1) reported that purified Taka-amylase was able to decompose α-phenylmaltoside into phenol and maltose. When the enzyme was first crystallized in pure state (2), it was reported that Taka-amylase A had no α-phenylmaltosidase activity. However, the amount of crystalline enzyme material was limited at that time and exact measurement could not be performed. Recently α-phenyl-maltoside as obtained in pure crystalline state, it has been made clear that the purified preparation of Taka-amylase A was able to decompose the maltoside to phenol and maltose when considerably high concentrations of the enzyme were used. Present paper deals with the experimental evidence in which Taka-amylase A showed both amylase and α-phenylmaltosidase activities, and it was further demonstrated that the determination of Taka-amylase activity with α-phenylmaltoside as substrate is a rapid and reliable method.