In order to rationalize structural maintenance, this paper focuses on vibration characteristics as indices to detect damage, and addresses advanced vibration measurement system and damage detection method based on changes in vibration characteristics. First of all, vibration measurement system using Laser Doppler Vibrometer, which can scan the objective structural surface, is developed and an identification method from laser ambient vibration measurement is proposed. Next, a damage detection method, which calculates mass and stiffness changes in reverse based on changes in mode shapes, is also constructed. These methods show their validity experimentally through vibration measurement for a steel plate before/after damage. Furthermore, to be applied for real civil structures which possess low laser reflection, the laser vibration measurement system is advanced with adding a function which can automatically search the maximum points of laser reflection. By means of this advanced laser vibration measurement system, vibration measurement on a reinforced concrete deck is carried out and its local mode shapes are identified.