In this paper we demonstrate a compact current sensor using the optic fiber micro wire, based on the idea of interferometrically measuring the thermally induced optical phase shifts as a result of heat produced due to the flow of electric current over short transit lengths. A responsivity of 1.28 x 10(-4) rad/I(2) at 50 Hz of current signal has been shown, with capability of measuring alternating current signals up to 500 Hz.