An air mattress include a plurality of air cell groups including a plurality of bladder-shaped cells and lined up with respect to the lengthwise direction of the air mattress so as to support at least a head area, shoulder area, back area, buttock, thigh area, knee area, and heel area of a person lying on the air mattress, an air supply/release pump; and an air tube connecting the bladder-shaped cells and the air supply/release pump in one or a plurality of independent first systems for each of the air cell groups out of the air cell groups and one or a plurality of independent second systems for each of specific bladder-shaped cells out of the plurality of air cell groups. Each of the air cell groups corresponding to the back area, buttock area, and thigh area includes a lower section of bladder-shaped cells and an upper section of bladder-shaped cells.