A fastening mechanism for an electronic device is provided. The electronic device is embedded into a fixed object, and has a display portion and an embedding portion. The fixed object is formed with a receiving space. A connection box is mounted in the receiving space. The fastening mechanism includes a fastening unit, an elastic unit and a transferring bracket. The fastening unit is movably disposed in the embedding portion of the electronic device. The fastening unit has a hook. The elastic unit abuts the fastening unit. The transferring bracket is disposed in the connection box, and has a frame and a blocking portion. When the embedding portion of the electronic device is disposed in the frame of the transferring bracket, the hook engages the blocking portion to fix the electronic device to the fixed object.