Abstract: A calibration method is provided for an IC tester which performs testing of ICs in association with a computer having a storage. A calibration file corresponding to results of calibration is stored by the computer. At first, the IC tester loads correction information representing results of a previous calibration from the computer. Then, a value of time propagation delay (TPD) is measured with respect to a pin selected from among pins of an IC and is compared with the correction information. The IC tester corrects a delay time provided for the pin whose value of TPD differs from the correction information. Thereafter, the correction information is renewed using the corrected delay time, so that the renewed correction information is stored by the computer. Thus, the IC tester completes the calibration prior to the testing of the IC.