This paper describes a method for the detection of changes in sleeping conditions using multipoint ambient sensing for safety and amenity in the sleep environment. This method continuously detects changes during sleep, such as the movements of the person and bedding based on the measurement of acceleration, temperature and humidity of the comforter. Through the measurement of these ambient conditions, this system improves sleep quality and prevents accidents, such as falling off the bed. In this study, a basic system using internet of things (IoT) devices is constructed, and performance verification is conducted. The experimental results show the feasibility of the proposed method.