PURPOSE: To improve a winding space factor as well as to reduce manhour in order to miniaturize a transformer, by dividing a tap winding into rough and fine sections which are respectively provided at the both ends and the intermediate position of a high-voltage winding.

CONSTITUTION: A tap winding is divided into a fine winding section 6 having a plurality of taps in which a tap delivery is drawn out from each tap having a voltage (e), and into rough tap winding sections 7-1 and 7-2 having a plurality of taps in which a tap delivery is drawn out from each tap having a voltage (2e). The winding sections 7-1 and 7-2 are provided on the both ends of a high- voltage winding 3A, 3B while the delivery thereof is connected to the neutral point N through a tap changer. The winding section 6 is provided at the intermediate position of the winding 3A, 3B.