PURPOSE: To measure the resistance of a thin film layer nondestructively by arranging a thin film layer to be measured on a carrying/supporting foil and moving the thin film layer on a roller having an eddy current type measuring unit embedded thereby detecting fluctuation of flux.

CONSTITUTION: To an inductor 2, an AC current for inducing a field reversely is fed from a high frequency generator 7, with and a normally resonant oscillation circuit 3 is constituted of the inductor 2 and a capacitor 4. The inductor 2 is provided with a cover 37 and embedded in a roller 20. A thin film layer 1 to be measured is set by deposition, for example, on a carrying designation foil 21 being carried on the roller 20. When the roller 20 turns to carry the carrying designation foil 21, an eddy current is induced in the thin film layer 1 by a field generated from the coil 2 which is thereby weakened. Consequently, resistance of the thin film layer 1 can be measured nondestructively by detecting the fluctuation of field in the form of fluctuation of a current i1.