It is difficult to measure the accuracy of a hole having a large length-to-diameter (L/D) ratio, e.g., a shaft of a jet engine, a cylinder used for plastic injection molding, a cylinder liner of an engine of a large ship, a cannon, etc. Further, the measurement accuracy depends on the measurement device. So far, laser-guided probes having a diameter of 110mm have been developed for measuring the accuracy of extremely deep holes. The accuracy is measured by scanning the wall of a hole spirally . Deep-holes can be bored using deep-hole drilling machine as well as by using a large lathe, a machining centre, a boring machine and so on. Even in the cases of holes with a relatively small L/D ratio, which are machined by the latter machines, it is difficult to evaluate their accuracies precisely. In this study, we have demonstrated how the accuracy of a machined hole can be measured on-machine; in addition, machining errors can be corrected during subsequent machining process used for finishing. Through experiments, it has been confirmed that the hole accuracy, e.g., straightness, roundness, etc., can be measured on-machine using the developed system.