The utility model relates to a fixing device for installing a third rail and a suspension type rail provided with the third rail. The fixing device comprises a fixed clamping part, a movable clampingpart hinged to the fixed clamping part, and a locking part. The fixed clamping part and the movable clamping part are respectively made of insulating materials, a cavity used for containing a rail bottom is formed between the fixed clamping part and the movable clamping part, and the locking part loosens or clamps the rail bottom arranged in the cavity by adjusting the included angle between the movable clamping part and the fixed clamping part. The fixing device provided by the utility model is compact in structure and convenient to install and use, can stably and firmly install and fix the third rail, and can effectively prevent the problem of looseness or local falling off in the actual use process; according to the suspension type rail, the third rail is arranged in the cavity of the rail through the fixing device, power supply is facilitated, the third rail can be effectively protected, and accidents such as electric leakage and electric shock are avoided.