To provide a shield tunnel boring machine which maintains a balance against a reaction force received from a bedrock, even when increasing an excavation speed, by establishing a method for effectively supplying power to a cutter head for crushing the bedrock for excavation of a tunnel such as an undersea tunnel at a great depth.

The cutter head includes a small-diameter inner cutter head 10, and a large-diameter outer cutter head 20 which is attached coaxially with the inner cutter head are provided. A rotational drive force is applied to a center shaft 16 which is connected to the inner cutter head 10 by a first cutter driving means 40; the rotational drive force is applied to an inner peripheral wall of an outer cutter head drum by a plurality of second cutter driving means 41; paths for transferring the rotational drive force to the inner and outer cutter heads employ inside and outside independent different systems, respectively; the rotational direction of the rotation of the inner cutter head 10 and that of the outer cutter head 20 are set as directions opposite to each other; and a bulkhead 30 is not rotated.