In an eddy current testing method which involves using a rotatable eddy current testing probe in which a detection coil is arranged within an exciting coil, a change in detection sensitivity (a deviation of detection sensitivity) which changes depending on the rotational position of the detection coil is reduced. The eddy current testing probe includes an exciting coil EC1, a detection coil DC1, an exciting coil EC2 and a detection coil DC2, which are mounted on a disk DS. The eddy current testing probe is placed so as to face a circumferential surface of an object to be inspected T, which is in the shape of a circular cylinder, and the disk DS is rotated. Then, the distance (liftoff) between the detection coils DC1 and DC2 and an inspection surface changes. Therefore, also the detection sensitivity to a flaw signal changes. To reduce the change in detection sensitivity, the detection sensitivity is adjusted by detecting the rotational position (rotational angle) of the detection coils DC1 and DC2.