Each of the models CS33EDTP and TCS33EDTP is an environmentally-friendly engine chain saw that reduces gas emissions with a catalytic muffler. In addition, I included certain operability and stable balance characteristics at a high level by the optimization of the handle shape. Moreover, a thumb rest (concave portion) is provided at the joint between the rear handle and the front handle to ensure stable operation in any direction. I installed a spring in the joint of a body and the handle to reduce vibration and a shock to burden the worker. And the (hanging) hook is convenient for the work at the high place.