To provide an on-load tap changer which can be simplified and reduced in size without impairing the necessary functions.

The on-load tap changer 1 is provided with a plurality of vacuum valve opening/closing mechanisms 1. Each of the mechanism is formed by coupling, with a coupling rod 4 for supporting the movable electrode 7, a vacuum valve device 2 accommodating a movable electrode 7, and a valve opening/closing mechanism 3 for driving to open or close the vacuum valve device 2. A tap is formed of current guiding means 17, 18, coupling rode 4, movable electrode 7 and fixed electrode 6. Each vacuum valve opening/closing mechanism 1 is provided with a tap power source switching function for switching the feeding of power source to the tap, under the condition that the movable electrode 7 of the vacuum valve device 2 is placed in contact with the fixed electrode 6 by driving to move forward and backward the elastic force holding mechanisms 9, 10, 11, 14 in the axial direction of the coupling rod 4 with the driving mechanisms 8, 15 and thereby these driving mechanisms are insulated.