PURPOSE:To increase the magnetic field in the horizontal direction on the surface of a material to be inspected and to increase the generating power, that is, generating Lorentz force of a generating coil, by bringing the magnetic body to come near the generating coil to decrease magnetic path resistance. CONSTITUTION:When high frequency pulse current IW1 is supplied to a generating coil 2 from a high frequency pulse power source 4, eddy current JW2 and oscillating magnetic field BW 2 are generated in a material 3 to be inspected. The oscillations of Lorentz force F2 are generated at the two-times frequency tuned to the frequency of the high frequency pulse current in the material 3 by the mutual effects of the eddy current and the magnetic field, and the oscillations propagate as ultrasonic waves in the material to be inspected. Here, laminated silicon steel plates 5 which are magnetic materials are provided to a transmitting transducer 1 to decrease the magnetic path resistance of the magnetic field generated by the current IW2. The generating power is thus made about twice higher and the flaw detection by the electromagnetic ultrasonic waves having high sensitivity is accomplished.