The objective of the present invention is to provide a mattress (10) including a plurality of cells (16) provided on a body pressure working surface of a substrate (20) that supports a human body, and a pressure control means (54) that changes a setting of a height of each cell (16) by adjusting a pressure in a fluid chamber (40) formed within the cell (16). An elastic cushion layer (22) is provided on a body pressure working surface of the cells (16), and a constricted portion (44) is formed in a middle in the height of the each cell (16) so that the body pressure working surface of the cell (16) is allowed to tilt following deformation of the cushion layer (22) as a result of the cells precession-deformation at the constricted portion (44).
