A memory stick having a metal housing, a PC board, a tray carrying the PC board, a lock body, and a locking mechanism. The lock body includes a positioning block press-fitted into a top opening of the metal housing and a locating block engaged into a top notch of the metal housing and adapted for accommodating an upper part of the tray and a part of an IC package circuit of the PC board for enabling the USB interface circuit to be suspending in a bottom opening of the metal housing. The locking mechanism enabling the memory stick to be locked to an external object.