The objective of the present invention is to provide a mattress including a plurality of cells provided on a body pressure working surface of a substrate that supports a human body, and a pressure control means that changes a setting of a height of each cell by adjusting a pressure in a fluid chamber formed within the cell. An elastic cushion layer is provided on a body pressure working surface of the cells, and a constricted portion is formed in a middle in the height of the each cell so that the body pressure working surface of the cell is allowed to tilt following deformation of the cushion layer as a result of the cells' precession-deformation at the constricted portion.