An improved USB connector extension/retraction device for a USB flash drive includes a moving cover for coupling with a flash memory unit (which has a USB connector), a resilient bar element, and two springs. The moving cover is assembled with a railed housing to form the USB connector extension/retraction device. The moving cover can be pushed forward and secured in position so that the USB connector of the flash memory unit is extended out for use. When not in use, the USB connector is retracted automatically so as to be hidden for protection. In addition, the USB connector extension/retraction device allows the USB flash drive to have a reduced volume.