To facilitate the labor of an eddy current examination by forming a probe body of a flaw detecting device for detecting flaws of piping, to be elastically deformable.

This flaw detecting device comprises a probe 13 connected to the tip of a cable 1 extending from a searching apparatus. A probe body 14 of the probe 13 is formed in cylindrical shape by wrapping gel material such as silicone rubber in an outer film 16 formed of rubber, and is elastically deformable by winding a specified quantity of coil 17 around the outer film 16. Both ends of the coil 17 pierce the outer film 16 to extend into the gel material 15 and pierce the outer film 16 near the cable 1 so as to be connected to wiring of the cable 1. In the case of making an eddy current examination of a heat transfer pipe, the probe 13 is inserted into the heat transfer pipe from the lead-in port of the heat transfer pipe, and the probe 13 is pushed into the inner part with air. When the probe 13 reaches a U-shaped bend part, the probe 13 is elastically deformed corresponding to the U-shape to pass through this part. The eddy current examination can thus be easily made.