This research proposes a walking promotion device using arm swing induced by parametric excitation. Generally, amplification of arm swing promotes a walking. The proposed device is worn on forearm. It has weight, linear rail and motor. Parametric excitation occurs moving the weight in the longitudinal direction of the forearm. The feasibility of the system is confirmed by the simulation by modeling the upper limbs and proposed device as serial links mechanism. Additionally, this simulation is conducted so that designing the mass of the device and movement of weight. Based on the result, the mass of the device is 0.43 kg, the movement of weight is 0.14 m, and the amplification rate is confirmed at 129.27%. In order to verify the simulation in the real system, 2-link pendulum was prepared. Comparing with two states of disabled and enabled, the shoulder joint angle increased 11.83° in average. In addition to this experiment, an evaluation experiment with human arm was performed. As the results, compared with simulation, the device can increase the arm swing at 10°.