Kawasaki Heavy Industries, Ltd. (KHI) has designed a compact free electron laser device that can provide a powerful and tunable (5–16 μm) light source. The FEL device consists of a 32 MeV accelerator, a beam transport system with two 25-degree bending magnets, an undulator of 40 periods and 32 mm period length, and a cavity mirror system. Using some computer codes to optimize the beam optics of the accelerator could provide a high-quality beam for the FEL.