A new method based on vibrating wire to measure field multipole is presented. The magnet multipoles are assessed by positioning the wire in different points on a circle inside the magnet aperture and measuring the amplitude of wire vibrations. An analytical model relates vibration amplitudes to multipoles. Results of simulation tests aimed at analyzing the model performance are reported. Preliminary experimental validation results on small permanent magnets for the new linear accelerator Linac4 at European Organization for Nuclear Research (CERN) are shown.