An inverter structure includes a power source and an uninterruptible power supply device. The uninterruptible power supply device includes a power output selector and a constant-current controller built therein. The uninterruptible power supply device has an input terminal connected to the power source and output terminals connectable to external electrical appliance facilities via the power output selector and the constant-current controller. When power is supplied from the power source, the power output selector and the constant-current controller built in the uninterruptible power supply device function to effect distribution of power output to the electrical appliance facilities in accordance with preset condition.