Handheld device and cradle head and electronic device using same

A handheld device (100), the handheld device (100) comprising a cover (110) and an electronic element provided within the cover (110). An expansion port (165) is provided on the cover (110) for connecting to the electronic device. The expansion port (165) is a heat-conducting port and extends from outside the cover to within the cover. The expansion port (165) can conduct heat generated by operation of the electronic element outside of the cover. Also disclosed is a handheld cradle head (1000) and an electronic device using the handheld device (100). The above handheld device (100) and handheld cradle head (1000) and electronic device using the handheld device (100) have a good heat dissipating function, and facilitate miniaturized design.