An encrypted hard disk device is provided, including a near-field communication (NFC) sensing module, a processor, a storage unit, and a power switch. The NFC sensing module is configured to read a user identification (UID) of at least one sensor element. The processor is electrically connected to the NFC sensing module and the storage unit. The processor receives the UID and generates a control signal when the UID is approved. The power switch is electrically connected to the processor and the storage unit and maintains a conducting state according to the control signal and supplies power to the storage unit for accessing the storage unit.