A USB flash drive, comprising a housing comprising internal walls defining a receiving space, at least one of the internal walls having an engagement component, a memory main body disposed in the receiving space and comprising a hook slot component, and a fastener disposed in the receiving space comprising a protrusion component and a hook component, the hook component engaged with the hook slot component of the memory main body, and the protrusion component engaged with the engagement component of the housing, thereby fastening the memory main body to the housing.