The invention discloses a transmission device of an ironing machine. The device comprises an ironing machine, a rack, a mounting rack, a first guide wheel, a first motor, a leather belt, an ironing belt, an entrance, a conveyor belt, a driving wheel, a second belt, a second motor, a fixing base, elastic elements, a movable base, a support guide wheel, a base, a driven wheel and an exit. The device has the advantages of being reasonable and simple in structure, low in production cost, easy to install and complete in function. While the device is used, first, clothes are flatly spread on the left side of the conveyor belt. Then, the first motor and the second motor are started simultaneously to drive the conveyor belt to move clockwise, and the ironing belt moves counterclockwise at the same speed. Next, the conveyor belt conveys the clothes from the entrance to the bottom of the ironing belt, and the ironing machine irons the clothes at the same time. As conveying and ironing are conducted at the same time, the efficiency of ironing is high. Besides, the whole ironing process is performed in the rack, which ensures high security.