An essential mechanical element in an industrial machine is a reducer, which transfers the rotation of an electrical motor or engine to another part with amplified torque. Some reducers, such as planetary reduction gears, a harmonic reducer, or a cycloid reducer, have been applied in various industries. Given the increase of demand for reducers with high precision, compact size, and high load capacity for use in industrial robots, the cycloid reducer has stood out. The cycloid reducer, compared with planetary reduction gears, has some merits, which include a larger reduction gear ratio at only one stage, higher durability, improved efficiency, and a larger torque because of its high tooth-contact ratio despite its being small. This paper presents a design technique for a cycloid reducer intended, because of those merits, for use in remote weapons systems of armed vehicles. In order to verify the performance of the cycloid reducer, we carried out experiments and analyzed the results systematically.