HONING DEVICE AND HONING METHOD

PURPOSE: To make machining time until reaching the target machined diameter constant so as to uniform the state of the finished surface between workpieces. CONSTITUTION: Air is sprayed toward a cylinder bore 17 from an air nozzle 47. The machined diameter of a cylinder bore 17 is thereby detected by an air micrometer 49, and the grinding quantity per unit time is computed by a computing circuit 51. When the grinding quantity per unit time to the cylinder bore 17 exceeds the predetermined grinding quantity per unit time, an expanding pressure control circuit 55 judges the machining speed to be too fast and lowers expanding pressure supplied by a hydraulic cylinder 23 so as to press honing sticks 29 to the inner surface of the cylinder bore 17. At the time of being less than the predetermined grinding quantity, on the other hand, the machining speed is judged to be too slow, and the expanding pressure is boosted to perform honing work.