The TBM cutter head is the frontmost part of a tunnel boring machine (TBM), and is responsible for cutting through the earth and rock in front of the machine. The cutter head is a large, cylindrical piece of equipment that is fitted with a number of cutting tools, typically made of steel. As the TBM moves through the earth, the cutter head rotates and the cutting tools grind away at the surrounding rock, creating a tunnel.

The cutter head is a very important part of the TBM, and must be able to withstand the immense pressure and wear and tear that is caused by cutting through rock. In order to ensure that the cutter head can handle these demands, it is made from very tough materials, such as steel or tungsten carbide. The cutter head must also be able to move freely, so that it can rotate and cut through the rock.