A contactless eddy current brake for cars is disclosed. In the brake, two cores are arranged around the edge of a brake disc while being spaced apart from each other at an angle of 90°. Each of the cores is wound with a coil, thus forming an electric magnet. A speed sensor is positioned around the axle, thus sensing revolutions of the wheel. A control unit calculates a DC or AC control current in response to a speed signal output from the sensor, thus outputting an appropriate control current value to the coils. A current amplifier supplies the control current value from the control unit or a current value from a brake pedal to the coils of the cores. The control unit allows a DC current to be supplied to the coils when the car runs at a high speed or allows an AC current with different phases to be supplied to the coils when the car runs at a low speed or is stopped on a slope. In such a case, the DC current is variable in accordance with a pedaling force, while the AC current is variable in the frequency in accordance with the pedaling force.