Purpose : The purpose of this study is to demonstrate the effectiveness of using a digital sensor device during CPR by analyzing the results from that chest compressions with a digital sensor device are applied to cardiac arrest patients. Methods : This study analyzed the results from the experiment that 42 people were selected randomly among Korean 119 rescuers, and they divided into the experimental group using a digital sensor device and the control group only using their hands, then they had been observed to conduct chest-compressions to mannequins for 10 minutes. Results : The results were found that compression depth in both the control and experimental group was gradually decreased over time, but the experimental group not only kept the depth but also maintained the speed of chest-compressions close to 100 times a minute. In addition, due to the use of the digital sensor device, the insufficient recoil ratio of chest-compressions was significantly reduced. Conclusion : The results show that conducting chest-compressions with a digital sensor device keeps the compression-death, maintains the speed of chest-compression properly and makes the insufficient relaxation ratio of chest-compressions reduce significantly.