PROBLEM TO BE SOLVED: To provide an apparatus that accurately acquires a users state in a bed by using a load sensor.SOLUTION: Three or more load sensors S are provided in positions different in a plan view in a bed so as to detect the weight of a user existing on a sleeping surface of the bed. A barycentric position computing unit 13, which determines the users barycentric position in a three-dimensional space on the basis of a detection value from the load sensors S, is provided.