An induction heating apparatus capable of heating a conductive plate member throughout in a widthwise direction is disclosed. Specifically, the present invention is configured to have flat-shaped coils, each forming a magnetic path in a center portion thereof, provided on upper and lower sides of the conductive plate member so as to heat the conductive plate member and to have circumferential coils provided on right and left end sides of magnetic metal casings through which the circumferential magnetic paths of the flat-shaped coils pass, whereby magnetic paths of the circumferential coils pass through both end portions of the conductive plate member.