To prevent decrease in accuracy of linear guide by detecting a load only at the time of oscillation of a tool applied to an equally divided bearing and a load when a load is applied, and controlling displacement of slide bearing by the difference therebetween.

When a clearance is generated between the slide surface of slide bearing 2 divided into three segments and the outer circumferenttial surface of a tool 1, caused by wear on the slide surface, the detected load by load detection parts 4a-4c, 4A-4C at the time of oscillation only in the same as that detected at the time of no substantial wear. However, when a load F is acts to an end of the tool 1, a load is applied to e.g. a part corresponding to the side of load detection parts 4b and 4c. The difference between the cases at the time of only oscillation and load F applied is calculated vby a control part, displacemetn control input levels 8a-8c, 8A-8C are supplied to a displacement control part, and the displacement control part is controlled by a piezoelectric element so that the detection load is the same as that at the time of no substantial wear on the slide surface. With the compensation mechanism, decrease in accuracy in the linear guide part of vibrating tool caused by increase in crearance can be prevented.