Functionally Graded Material (FGM) has been developed as the element that can stand at high temperatures. FGM is a non-homogeneous material and information about distribution of thermo-physical properties is demanded to evaluate its heat resistance. So we develop a new method to measure thermo-physical properties using induction heating. However distribution of electric conductivity in the material must be estimated so that a depth of induction heating is dependent upon the conductivity. Then a method to measure the distribution is investigated by detecting intensity of electromagnetic field and phase difference of that at induction heating. The method uses a theoretical solution for the data reduction on the assumption that FGM is a multi-layers material composed of various substances differing in property. A single layer material is studied as fundamentals of multi-layers material. This report describes a comparison between analyses of electromagnetic field and experiments of that.