In human hand, there are numerous energy sources such as finger bending and grasping. In previous studies, most energy harvesters have been attached to joints. Herein, we use another energy source during finger bending motion. Specifically, we focus on the shape change of the finger from bending and propose a ring shaped piezoelectric energy harvester. It consists of an anterior piezoelectric ring and an exterior silicone ring. We utilize a silicone cylinder to mimic the finger shape change situation. We measure and observe electrical responses from the piezoelectric energy harvester for the finger shape change.