A superconducting magnet for the Fixed Field Alternating Gradient (FFAG) accelerator has been proposed. The static magnetic field is required to be proportional to the k-th power of the orbit radius where k is the geometrical field index of the accelerator. A left/right asymmetric coil with elliptical aperture is utilized to maximize the horizontal aperture with a compact design. The saddle shaped coil configuration is designed to fulfil the design requirement in terms of integral magnetic field along an arc orbit. In a beam tracking simulation, a particle was circulated and accelerated with the magnetic field generated by the designed coil. A prototype superconducting coil with a cylindrical bore was developed and the field quality was evaluated at warm field measurement