This paper describes a light-weight method for hand-waving gesture detection. Gesture recognition is actively researched as a user interface of robots. Conventional gesture recognition methods need to employ complicated pattern matching algorithms, such as DTW, HMM, and DNN, which require a powerful computing platform such as fast CPU or GPU that consumes much energy. We propose a gesture recognition/detection method specially designed for the recognition of hand-waving gesture. This method uses Kinect V2 as the sensor and detects the waving gesture using only a simple signal processing. The recognition experiment suggested that the proposed method gave sufficiently high accuracy, and the processing speed was much faster than real-time.