AbstractA micro‐eddy current testing (ECT) probe, which consists of a planar microloop inductive magnetic sensor array and a pancake‐type exciting coil, was developed to upgrade the ECT technology, especially as it is used for inspecting steam generator tubing in a pressurized nuclear power plant (PWR). Eddy currents and resultant magnetic fields are perturbed due to a flaw in a conductor. The flaw is detected via perturbation of the electromotive force (EMF) and phase from the array. Flaws manufactured by electric discharge machining in INCONEL 600 planar specimens, the thickness of which was 1.25 mm, were detected and reconstructed by using stacked database and simplified algorithm. Even an outer‐edged 10 percent flaw could be detected. Measured EMF and phase signals were compared with numerical results obtained by using a three‐dimensional eddy current and field analysis code and then verified. The experiment confirmed that the spatial resolution of detection of the micro‐ECT probe is superior to that of the conventional pancake‐type ECT probe. Finally, it was demonstrated that it is possible to establish the same measurement speed using the micro‐ECT probe as it is by using the pancake