To provide a shield machine which can reduce abrasion of a cutter bit by emitting a jet of water to natural ground through the use of an inexpensive constitution.

In this shield machine, a cutter head 3, to which the cutter bits 15 are attached, is rotatably provided at the front end of a shield body 1; a water ejecting hole 21, which is opened forward, is formed in the front part of an outer peripheral wall part 1a of the shield body 1; a water supply pipe 23 for supplying the water is connected to the hole 21; and the cutter head 3 is formed in such a size that its outer peripheral end surface is located to the center of rotation with respect to the hole 21 which is formed in the shield body 1.