Recently many researchers are focused on cell stimulation regarding observation of cells to specific stimulation factors. We introduce new mechanical stimulation method using micro beads without any chemical reagents. CPAE (calf pulmonary artery endothelial cell) were cultured in PDMS (polydimethylsiloxane) microfluidic device. After starvation process, sterilized 10|im glass beads were rolled by only gravitational force for 10 minute. To find optimal stimulation time, 16 devices were made by PDMS and each device was slanted every hour. Results show that cell exposed under micro bead stimulation perform at a higher growth rate than normal conditions and 1 hour stimulation time represents more effective than other stimulation times. This new cell stimulation method will be able to help make artificial organ such as blood vessels in the future.