The paper examines the dependence of vibro-acoustic oscillations spectrum arising in cutting zone (on the example of gear-broaching tool) on the cutting edge wear. On the basis of analysis of the vibrational spectrum the method and control device for machining facilities are developed. The device is processing the frequency and correlation signal from vibration sensor, fixed in the location of the workpiece. Increased wear of cutters leads to increasing in analog output voltage in the control device. The authors have conducted tests and monitoring of tool wear. The readout correlated with the visual identification of the width of the front cutting edge of the tool.