A swivel-type portable flash device includes a C-shaped swivel cover that rotates (swivels) relative to a housing between an open position in which a plug connector is exposed for insertion in a host system, and a closed position in which the plug connector is covered and protected by the swivel cover. The swivel cover is permanently rotatably connected to the housing by ring-shaped protrusions that are movably engaged inside corresponding recessed ring-shaped grooves formed in upper/lower walls of the housing, whereby the swivel cover is manually rotatable relative to the housing between the opened and closed positions. The swivel cover includes locking structures (e.g., locking notches) disposed on the ring-shaped protrusions, and the housing includes second locking structures disposed in the recessed ring-shaped grooves, where the first and second locking structures prevent rotation of the swivel cover when the plug connector is closed.