The present paper proposes an efficient contactless measurement method for vibration stress of piping systems, by which the measuring works are performed for an extreme short time and the measured stress can be evaluated immediately after the measurement. The proposed method uses only one LED-optical sensor to measure the vibration stress though multiple sensors must be used in the previous method developed by the authors. Therefore, the measuring system could be reduced in size and a light-weight and portable measurement instrument was developed. The measurement accuracy and reliability of the new method were verified by vibration experiments using a mock-up piping.