A new planar-type high frequency current detector utilizing the skin effect in a pair of 6mm x 10mm x 5μm permalloy plates is developed. The high frequency current of up to 100MHz is supplied through impedance matched microstrip lines. The detector characteristics were analyzed using an equivalent circuit technique. Comparison of the calculation with measured operation clarified the usefulness of the analysis on the design of the detector, and also the influence of the stray capacitances on the high frequency operation, quantitatively. As a result, the present detector is applicable up to 60MHz.