There are provided a thin transformer capable of being used in a slim display device such as a liquid crystal display (LCD) device and a light emitting diode (LED) display device, and a flat panel display device including the same. The transformer includes: a bobbin part including a plurality of bobbins, each including a pipe shaped body part having a though-hole formed in an inner part thereof and a flange part protruding outwardly from both ends of the body part; coils respectively wound around the bobbins; and a core electromagnetically coupled to the coils to thereby form a magnetic path, wherein at least one of the bobbins includes a coil skip part which is a route through which lead wires of the coil skipped through the flange part is disposed on an outer surface of the flange part.