Abstract: An objective of the invention is to provide an integral air mattress capable of preventing caving-in. To achieve the above objective, the present invention provides an air mattress consisting of three sheets 1 to 3 stacked and airtightly sealed at their circumferential portions, the mattress comprising: first-layer air cells 6a and 6b consisting of tubular air cells formed widthwise by the first and second sheets 1 and 2; and second-layer air cells 8 consisting of tubular air cells formed widthwise by the second and third sheets 2 and 3, wherein the first-layer air cells 6a and 6b and the second-layer air cells 8 are arranged so as not to overlap in the longitudinal direction. The overlying first-layer air cells 6a and 6b are set at low pressure so as not to cause bedsores easily, while the underlying second-layer air cells 8 are set at high pressure so as not to cause caving-in easily.