A tunnel boring machine, comprising: a main body; a cutter head that is disposed in front of the main body and is rotatable with respect to the main body; a plurality of disc cutters rotatably mounted on the cutter head, each of the disc cutters including a cutter ring that is exposed to a front surface of the cutter head while exposed to a back surface of the cutter head, the cutter ring including a cutting edge part; and an acquisition unit that is disposed behind the plurality of disc cutters to acquire cutting edge position data indicating a position of the cutting edge part, characterized by further comprising: a discrimination unit for discriminating which one of the plurality of disc cutters is the disc cutter cutting edge position data of which is acquired by the acquisition unit; and a calculator for calculating a wear amount of the cutting edge part of the disc cutter discriminated by the discrimination unit based on the cutting edge position data of the discriminated disc cutter, wherein the discrimination unit detects distance from a center of the cutter head to the cutting edge part of each of the plurality of disc cutters, or detects a rotation angle of the cutter head with respect to the main body to discriminate a disc cutter among the plurality of disc cutters. a main body; a cutter head that is disposed in front of the main body and is rotatable with respect to the main body; a plurality of disc cutters rotatably mounted on the cutter head, each of the disc cutters including a cutter ring that is exposed to a front surface of the cutter head while exposed to a back surface of the cutter head, the cutter ring including a cutting edge part; and an acquisition unit that is disposed behind the plurality of disc cutters to acquire cutting edge position data indicating a position of the cutting edge part, characterized by further comprising: a discrimination unit for discriminating which one of the plurality of disc cutters is the disc cutter cutting edge position data of which is acquired by the acquisition unit; and a calculator for calculating a wear amount of the cutting edge part of the disc cutter discriminated by the discrimination unit based on the cutting edge position data of the discriminated disc cutter, wherein the discrimination unit detects distance from a center of the cutter head to the cutting edge part of each of the plurality of disc cutters, or detects a rotation angle of the cutter head with respect to the main body to discriminate a disc cutter among the plurality of disc cutters. a discrimination unit for discriminating which one of the plurality of disc cutters is the disc cutter cutting edge position data of which is acquired by the acquisition unit; and a calculator for calculating a wear amount of the cutting edge part of the disc cutter discriminated by the discrimination unit based on the cutting edge position data of the discriminated disc cutter, wherein the discrimination unit detects distance from a center of the cutter head to the cutting edge part of each of the plurality of disc cutters, or detects a rotation angle of the cutter head with respect to the main body to discriminate a disc cutter among the plurality of disc cutters.