An eddy-current flaw detection method includes a synchronization step (S3, S4) of synchronizing the phase of an exciting voltage applied by coil driving means to an exciting coil for generating an eddy current in a test object with the phase of a driving voltage, higher in frequency than the exciting voltage, applied by device driving means to a magnetoimpedance effect device for detecting the variation of a magnetic field arising in the exciting coil; and a magnetic field detection step (S5) of detecting the variation of the magnetic field arising in the exciting coil due to the eddy current generated in the test object using the magnetoimpedance effect device.
