To improve the adhesion and transmission efficiency between the upper and lower facing cores of a non-contacting type transformer housing wound coils in concentric grooves, by sticking a highly slidable insulator to the upper core of the facing magnetic cores of the transformer.

A non-contacting type transformer 10 is provided with a pair of doughnut-like ferrite cores 11 and 12 and a magnetic sleeve 3a composed of winding sections 2 (2a-2d) housed in concentric and radial grooves 5 (5a-5d) provided on the cores 11 and 12 and a magnetic steel plate. The magnetic sleeve 3a is fixed to the upper ferrite core 11 with an adhesive and an outer holder 41, Four guide holes 13 are made through the outer holder 4a for vertically moving the ferrite core 12. In addition, bar members 14 are protruded downward from an inner holder 4b on the lower ferrite core 12 side correspondingly to the positions of the guide holes 13 of the outer holder 4a. The upper and lower ferrite cores 11 and 12 are coupled with each other through the outer holder 4b and a coil spring 8. In addition, an insulating layer 7 is formed on the surface of the upper core 11 facing the lower core 12.