The disclosure provides a portable charger including a power supply and an adapter. The power supply includes a battery module, a first terminal set, a voltage control module and a first switch portion. The battery module has an initial voltage. The adapter includes a second casing, a second terminal set, an output connector and a second switch portion. When the adapter is detached from the power supply, the portable charger is in a first state, and the voltage control module adjusts the initial voltage to a first voltage, allowing the first terminal set to output the first voltage; when the adapter is disposed on the power supply, the portable charger is in a second state, and the voltage control module adjusts the initial voltage to a second voltage which is different from the first voltage, allowing the first terminal set to output the second voltage.