A flash memory device includes a main body, a cover and an elastic member connecting the main body and the cover. The main body includes a hinge protrusion formed thereon. The cover includes a tail and a pair of parallel plates facing each other and spaced by an interval corresponding to a thickness of the main body. At least one plate defines an opening for receiving the hinge protrusion so that the cover is rotatable with respect to the main body. The elastic member is fastened to the cover to abut against the protrusion, or fastened to the main body to abut against the cover, when the cover is rotatable relative to the main body.