The invention discloses a collar ironing device. The device comprises a placement plate, a heat conduction ironing inner body is arranged on the placement plate, and the side wall of one end of the heat conduction ironing inner body is fixedly connected with the placement plate; a first through hole allowing the other end of the heat conduction ironing inner body to penetrate through is formed inthe inner side face, close to the fixed end, of the heat conduction ironing inner body; an adjusting mechanism is arranged on the placement plate; a rack is provided with an annular guide rail which rotates around the heat conduction ironing inner body, and a second driving part which drives the guide rail to rotate; a supporting arm extending towards the outer peripheral wall of the heat conduction ironing inner body is fixedly arranged on the guide rail, a fixing rod is slidably arranged in the supporting arm in the length direction of the supporting arm, and a heat conduction ironing outerbody is rotationally arranged at the outer end of the fixing rod; a third driving part for driving the fixing rod to slide back and forth is arranged on the supporting arm. The device has the advantages that collars in different sizes can be ironed, and a better ironing effect is achieved.