Abstract: A tunnel excavating machine for generating tunnels and galleries in subterranean structures, comprises in addition to the excavating head, a shield which travels with the head and advances along the excavation and lines the tunnels wall at least temporarily. According to the invention, the shield is formed by at least two shield sections which are preferably cylindrical and can be axially spaced apart while being bridged by a seal for the gap between them. The two shield sections are connected by a plurality of angularly equispaced piston-and-cylinder arrangements preferably of the double-acting type to allow angular offsetting of the axes of the two shield sections.