The purpose of this study is to compare amylase and peroxidase activities of the healthy paulownia tree with those of the diseased tree affected by witches' broom, and to intend to explain the abnormal metabolism of the diseased tree. Amylase activity was determined by Wohlgemuth's method and peroxidase activity was estimated by Willstatter's method. The results were as follows. 1. Amylase activity of the diseased leaves was superior to that of the healthy leaves at the rate of 116:100 in July, 122:100 in September and October. This indicated that amylase activity was slightly greater in the diseased leaves than in healthy ones. 2. Peroxidase activity of the diseased leaves was superior to that of the healthy ones at the rate of 120:100 in August, 138:100 in September and 303: 100 in October. This indicated that peroxidase activity was always greater in the diseased leaves than in healthy ones. No contradiction exists between the increase of amylase activity and the abnormal accumulation of starch within the same diseased leaves mentioned before, because as it is known that the break-down of starch takes place in the leaves under other enzyme, phosphorylase. Both abnormal increase of respiration of the diseased trees, mentioned before, and the increase of peroxidase given by the present paper, may clearly be explained if peroxidase is considered to play a part of respiration as a terminal oxidase of paulownia tree.