<p>A transformer according to an embodiment of the present invention includes a first transformer unit which includes a first core and a first coil; a second transformer which faces the first transformer and includes a second core and a second coil; and an insulation substrate which controls a creep distance between the first transformer unit and the second transformer unit and includes a third coil. A first transformer unit receiving groove to receive the first transformer unit is formed on the insulation substrate. The third coil is formed in the first transformer unit receiving groove.</p>
