This paper demonstrates the crack detection of thick‐walled non‐magnetic metal plates by eddy current testing, which used to be difficult because of the skin effect generally. For the purpose, this paper proposes a novel eddy current testing probe for cracks in thick‐walled plates and evaluates the capability of the present probe. The probe was designed, based on the numerical computation using 3D fast eddy current code. The advantages of the present probe are strong eddy current on the back of specimens and small decay of eddy current in the thickness direction. Through experiments, we confirmed that this probe can detect the back artificial defect on INCONEL718 specimen with thickness of 7.0mm and 304 Stainless steel specimen with thickness of 8.0mm. © 2003 American Institute of Physics