A built-in electric air pump mounted on an inflatable bed by heat binding or adhesion is provided, and includes a pump housing; an air duct conversion mechanism mounted in the pump housing; a cover assembly covering the pump housing; a switch assembly connected with the air duct conversion mechanism; an air valve assembly disposed on the bottom of the pump housing; and a power source device connected with the switch assembly and powering the air pump. The air pump receives power from combinations of power sources in four different modes, namely, dry batteries, a rechargeable battery pack assembly, a vehicle-mounted power source and an AC adapter which match one another, to drive the pump, thereby forming multiple power source configurations to drive the same set of air pump and enable the same inflatable bed to be used indoors as well as outdoors at any time.