An electronic device enclosure includes a computer case, a mounting tray for receiving an expansion card and a fastening member. The computer case includes a front plate. A positioning slot and an opening are defined in the front plate. The fastening member includes a main body attached to the mounting tray and a latching plate connected to the main body. The latching plate is positioned in the positioning slot. An inserting portion is located on the latching plate and elastically engaged in the opening.