In order to develop techniques for quick and accurate assessment of damage to piles following major earthquakes, authors have been conducting a series of researches on the development of monitoring techniques to detect damage to concrete piles. In Part I, the sensor using carbon fiber has been proposed, and its applicability has been shown by various kinds of tests on carbon fiber and the sensor. In this paper, the performance of the sensor to evaluate the integrity of concrete piles is investigated. Firstly, the required performance in monitoring the integrity of piles is discussed in relation to the different types of damage to piles. Secondly, the applicability of the carbon fiber sensor to monitoring is discussed based on the results obtained by bending tests of piles. Finally, results of various tests of piles are shown to demon- strate the applicability of the technique in actual practice.