This study describes a measuring instrument based on the Michelson interferometer. It is able to measure the amplitude-time function or the resonance curve in a wide frequency range simultaneously depending on the amplitude of the vibration without any kind of mechanical contacts. Compared with other instruments based on similar principles, it has the advantage of not being a heterodyne interferometer, that is of using only the phenomenon of classic interference instead of the frequency of Doppler shift of the reflected light. The reflective surface of the oscillating object or the mirror glued thereon may turn, which is often the case. The software performs a correction to the errors arising from the turning of the mirror. In the realized instrument the allowed maximum angle of rotation of the mirror is ±5°, measuring range of the amplitude is 5 micron to 1 mm, measuring range of the frequency is 1 Hz to 5×10⁴ Hz depending on the amplitude. © 1997 American Institute of Physics.