The invention discloses a differential probe device used for metal film thickness measurement. The device comprises an excitation source which is used for providing an oscillation source, a differential probe which is provided with a first coil channel and a second coil channel, and correspondingly comprises a first coil and a second coil, an acquisition module which is used for generating a magnetic field directly under the probe, and collecting the equivalent impedance of the probe when an induced magnetic field is generated on the surface of a measured metal film directly under the probe, and a central processing module which is used for enabling the first coil and the second coil to work simultaneously, and acquiring the variation value of the coil impedance according to the equivalentimpedance to acquire the thickness of the measured metal film according to the variation value of the coil impedance. The device can measure the thickness of the metal film in a non-contact manner, which reduces the interference of common modulus and improves the test stability.