In the quality control for cast-in-situ piles, it is hard to estimate the condition of piles after the concrete placing. Therefore, the tape measure is used generally for depth measurement of the excavated hole just after drilling. However, it is feared that the pile shape is different from the design one by the influence of ground water. Far the purpose of researching the applicability of the integrity test that is a nondestructive method, we carried out field tests in 26 sites of nationwide. The following results are obtained from the tests: (1) Integrity tests are useful for the estimation of the pile length, however, errors (about 3%) are included in test results, (2) If the stiff middle layer exists, estimation errors will increase, (3) Statnamic testis fully practical for relatively short piles.