CALIBRATION METHOD, CALIBRATION JIG AND TUBE INSPECTION METHOD

PROBLEM TO BE SOLVED: To provide a stable calibration method for a test piece for calibration, in which movement in a direction crossing an axis direction of a sensor and eccentricity from an axis center of the test piece for calibration are suppressed.SOLUTION: A tube inspection device 1 includes: a cable 5 which is bendable and is inserted into an inside of a tube; and at least a sensor 9 for inspecting a state inside the tube and stabilizers 11 for adjusting an axis center position of the cable 5, which are both arranged along the cable 5 in the axis direction thereof with spaces being provided therebetween. A calibration method using the tube inspection device 1 comprises: inserting the tube inspection device 1 into the inside of a test piece 15 for calibration simulating a linear portion of the tube and having a penetration hole 19 therethrough; and calibrating the sensor 9 by a detection signal outputted from the penetration hole 19. Before inserting the tube inspection device 1, a tubular member 17 is fitted on the inner surface of the test piece 15 for calibration, the tubular member having a predetermined thickness and being composed of a material with no influence on the detection signal.