The present invention relates a tool changer controlling method and apparatus, which can reduce a tool changing time as compared with the prior art. The controlling apparatus controls operation of a tool changer (1) which comprises a changer arm (2) for holding tools (Ta,Tb) and is adapted to pivot the changer arm (2) by a driving system including a servo motor (5) and exchange the tool (Ta) attached to a main spindle (20) in a tool changing position and the tool (Tb) in a predetermined position. The servo motor (5) is driven and controlled so that the changer arm (2) is preliminarily pivoted by a predetermined angle when the main spindle (20) is moved to the tool changing position, and further pivoted to the tool changing position after the main spindle (20) reaches the tool changing position.