In this paper, we propose a method for supporting a walking of a human by using wearable walking support system called Wearable Walking Helper. In this method, the support moment for the knee joint of the user is calculated by the human model and a part of it is supported by the actuator of the Wearable Walking Helper. In the conventional method we proposed so far, we only consider the stance phase of the gait which requires a large moment of the knee joint in walking for supporting the weight of the user. In this paper, we especially focus on the support of the swing phase of the gait which requires a moment of knee joint for supporting not only the weight of the leg but also the weight of the Wearable Walking Helper itself. For realizing the swing phase support, we measure an inclination of the upper body of the user with respect to the vertical direction by using the accelerometer and apply it to the calculation method using human model for deriving the support moment of the knee joint. The proposed method is applied to the Wearable Walking Helper experimentally and the experimental results illustrate the validity of the proposed method.