A built-in electric air pump for an inflating object includes a pump casing, a switch hand-wheel, a connection pipe, an air passage switching device, an air pump, and an air valve and a power switch. The pump casing includes a box-shaped chamber. The switch hand-wheel is provided at an external lateral side of the panel. The air passage switching device is provided with an internal pipe having a first opening and a second opening respectively arranged at an upper end and a lower end of the internal pipe. The first opening communicates with outside of the inflating object, and the second opening communicates with the air valve. A diaphragm is provided inside the internal pipe. A first venting hole and a second venting hole are respectively provided on internal walls at two sections of the internal pipe above and below the diaphragm. An external sleeve is provided outside the internal pipe. The lower end of the external sleeve is fixedly connected to the pump casing. The lower end of the external sleeve correspondingly communicates with the air valve. A wall of the external sleeve is provided with an air outlet communicating with an air inlet of the air pump and an air inlet communicating with an air outlet of the air pump. An upper end of the connection pipe is connected to and communicated with the switch hand-wheel, and the lower end of the connection pipe is muff-coupled with the upper end of the internal pipe. The diaphragm of the internal pipe contacts a valve rod of the air valve such that the valve is opened by an applied external force and the diaphragm and the value are moved together.