To obtain a method and an apparatus, in which a noise generated by a peripheral apparatus is discriminated and in which the polished state of a material to be polished can be monitored with high accuracy by a method, wherein a response waveform from the material to be polished at a point of time when a shock vibration is given to the material to be polished is detected, the response waveform is data- analyzed, and the polished state of the material to be polished is monitored.

A strain gage 32 detects a response waveform (qa) generated by a vibration between a wafer 5 to be polished and an abrasive cloth 23 at a point of time, when an impulse vibration is given to the wafer 5 to be polished, and the response waveform (qa) is sent out to a polished-state monitoring circuit 33. The polished-state monitoring circuit 33, to which the response waveform (qa) detected by the strain gage 32 is input, data-analyzes the response waveform (qa), and it monitors the polished state of the wafer 5 to be polished. That is to say, on the basis of the magnitude of the damping factor of the response waveform (qa), the property of the worked face of the wafer 5 to be polished is found. As a result, it is possible to obtain a polishing method in which noise is discriminated and in which the polished state of the wafer to be polished can be monitored with high accuracy.