A method of measuring a property of an object with acoustically induced electromagnetic waves comprising the steps of: irradiating a measurable object with acoustic waves; and measuring electromagnetic waves generated from said measurable object to determine any one of properties of the object, including its electrical, magnetic and electromagnetic mechanical properties, from any one or a combination of strength, phase and frequency characteristics of said electromagnetic waves; characterized in that the acoustic waves with which said measurable object is irradiated are in the form of: acoustic waves of a fixed frequency in a narrow band or acoustic wave pulses of a fixed frequency in a narrow band, in which cases said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object with the fixed frequency of said acoustic waves as a reference signal and the heterodyne or phase detection of a signal resulting from said detection with a frequency of said acoustic waves; or acoustic wave pulses of a fixed frequency in a narrow band, in which case said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object with the repetition frequency of said acoustic wave; pulses as a reference signal and the heterodyne or phase detection of a signal resulting from said detection with a pulse repetition frequency of said pulses. irradiating a measurable object with acoustic waves; and measuring electromagnetic waves generated from said measurable object to determine any one of properties of the object, including its electrical, magnetic and electromagnetic mechanical properties, from any one or a combination of strength, phase and frequency characteristics of said electromagnetic waves; characterized in that the acoustic waves with which said measurable object is irradiated are in the form of: acoustic waves of a fixed frequency in a narrow band or acoustic wave pulses of a fixed frequency in a narrow band, in which cases said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object with the fixed frequency of said acoustic waves as a reference signal and the heterodyne or phase detection of a signal resulting from said detection with a frequency of said acoustic waves; or acoustic wave pulses of a fixed frequency in a narrow band, in which case said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object with the repetition frequency of said acoustic wave; pulses as a reference signal and the heterodyne or phase detection of a signal resulting from said detection with a pulse repetition frequency of said pulses. acoustic waves of a fixed frequency in a narrow band or acoustic wave pulses of a fixed frequency in a narrow band, in which cases said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object with the fixed frequency of said acoustic waves as a reference signal and the heterodyne or phase detection of a signal resulting from said detection with a frequency of said acoustic waves; or acoustic wave pulses of a fixed frequency in a narrow band, in which case said electromagnetic waves are measured by heterodyne or phase detection of the electromagnetic waves radiated from said measurable object with the repetition frequency of said acoustic wave; pulses as a reference signal and the heterodyne or phase detection of a signal resulting from said detection with a pulse repetition frequency of said pulses.