Eddy current flaw detecting probe

The present invention provides an eddy current flaw detecting probe to be used for maintenance and detection of a heat transfer pipe in a heat exchanger of a nuclear power plant. Namely, the eddy current flaw detecting probe comprises an approximately columnar or approximately cylindrical flaw detecting main body to be inserted to a metal tube. A wire is wound on the circumferential surface of the flaw detecting main body circumferentially substantially uniformly and substantially in parallel with each other to form a bobbin type coil having a predetermined width to be used exclusively for excitation. A number of surface coils such as pancake coils are disposed on the bobbin type coil over the entire circumference of the main body of the bobbin type coil. Then, since the bobbin type coil to be used exclusive for excitation forms uniform and strong streams of eddy current in the circumferential direction of the tube, electric fields caused by the eddy current which is disturbed by a cracking in axial direction can be detected by the surface coils. As a result, detection for the failure in axial direction can be improved remarkably. (I.S.)