To inhibit a tap switching operation from being performed when a changeover switch of an on-load tap switching device is inoperable.

An on-load tap switching device comprises an accumulation drive mechanism 1 including a spring 6 which is accumulated with a revolution of a center shaft 8 driven by a manipulator, a latch mechanism 11 which latches the spring 6 until the accumulation of the spring is completed, and a displacement transfer mechanism 12 which converts displacement of the spring which occurs when the latch of the spring 6 is released into rotational displacement and transfers it to a changeover switch. The on-load tap switching device further comprises a stopper mechanism 50 and a mechanical weak point part 9a. When such a mechanical fault occurs that the changeover switch cannot be operated even after the latch of the spring 6 by the latch mechanism is released, the stopper mechanism 50 blocks the revolution of the center shaft 8. The mechanical weak point part 9a is broken when a drive force is applied from the manipulator while the revolution of the center shaft 8 is blocked.