Provided is a transformer having a noise reducing means. The transformer includes: an iron core (P), which is formed by stacking a plurality of steel sheets, and has stepped parts (S) formed at a portion thereof with different widths; and the noise reducing means provided at the stepped parts (S) so as to increase coupling force among the plurality of steel sheets. The noise reducing means includes: pressing bars (30) mounted on the stepped parts (S) of the iron core (P), and having plane-shaped horizontal pressing surfaces (31) in the direction in which the steel sheets are stacked; and a binding (90) for surrounding the outer surface of the iron core (P) including the pressing bars (30), so as to press the pressing bars (30) in the stacking direction of the steel sheets.