This paper presents a signal detection method based on an integer-type Haar lifting wavelet transform. We apply it to electrocardiogram (EGG) signal processing. First, we propose a method for learning free parameters contained in this transform. We learn these parameters so that the ratio of a lifting wavelet coefficient to a corresponding old one is two. We utilize the value as an indicator to identify the target signal. As a practical application, we employ the method to detect characteristic waves in EGG signals. The proposed method is also suitable to make a real-time signal detection system with a small amount of hardware.