A charging device includes a power converting unit and a power output unit. The power converting unit comprises a first conductive pin, a second conductive pin, and a converter. The first conductive pin and the second conductive pin are electrically connected to an alternating current (AC) power. The converter converts the AC power to a direct current (DC) power and outputs the DC power. The power output unit is electrically connected to the converter via a number of cables, and outputs the DC power to an electronic device. The power output unit comprises a first switch and a second switch. When the electronic device separates from the power output unit, the first switch controls the converter to stop receiving the AC power. When the electronic device is completely charged, the second switch controls the converter to stop receiving the AC power.