When, at the initial operation of an air mattress having inflating and deflating functions or at restarting after maintenance, many air cells need to be filled with a large amount of air, the air supply/discharge pump is operated at a driving force (the first power output) close to the maximum driving capacity thereof in order to inflate the air cells as soon as possible. In the normal operation in which the bed user is lying on the bed, when the air supply/discharge pump needs to be driven in order to cause alternate inflation and deflation or in order to prevent the user from touching the bottom, the air supply/discharge pump is driven at a second or third power output lower than the first power output. Thereby, it is possible in the air mattress having inflating and deflating functions to achieve rapid pressure adjustment and alleviate bed users discomfortable feeling due to the operation noise of the pump upon the pressure adjustment.
