本发明揭示一种平面变压器,其系包括有:以一磁性物质所形成之一第一平面磁芯;一下部次级绕组,其设置系用以封闭该第一平面磁芯之一第一左梁于该第一平面磁芯之一第一后梁以及一第一前梁之间;一初级绕组,设置于该下部次级绕组之上,以封闭该第一平面磁芯之第一左梁与第一右梁;一上部次级绕组,设置于该初级绕组之上,以封闭该第一平面磁芯之第一左梁;以及一第二平面磁芯,设置于该上部次级绕组之上。; a primary winding which is disposed on the lower secondary winding so as to enclose first left and right sills of the first planar core; an upper secondary winding which is disposed on the primary winding to enclose the first left sill of the first planar core; and a second planar core disposed on the upper secondary winding.