The influence of most physical factors on the revelation ability of magneto-optic eddy current defectoscopy of linear defects in metallic objects is investigated. Uniaxial anisotropy multi-component Bi-substituted garnet film is used as the sensor element. The efficiency of visualization depends on frequency and amplitude of the inducer’s electric current and the biasing magnetic field. Optimal values of these parameters are obtained. It is shown that the alternative magnetic field exerts the most influence on the eddy current magneto-optic image.