PURPOSE: To conduct feedback of the diameter correction value corresponding to the room temperature so as to improve machining accuracy by making the change of the finished diameter errors of cylinder bore inner diameters between workpieces corresponding to the room temperature continuous even when the action of a honing device is stopped.

CONSTITUTION: Even when the action of a honing device is stopped, a coolant is continuously fed from a coolant nozzle 23 by a coolant feeder 25. The thermal stability of a cylinder block 9 is thereby kept, and the change of the finished diameter errors of cylinder bore inner diameters between workpieces corresponding to the room temperature becomes continuous. Moreover, the coolant is jetted upward from the coolant nozzle 23 provided at the lower part of the cylinder block 9, so that the coolant is prevented from entering a water jacket 10, and the takeout of the coolant to an after-process after the end of honing is prevented.