The invention relates to an electromagnetic heating device of an iron finishing roller of an iron finishing machine. The electromagnetic heating device comprises an upper heating cover assembly (17) and a lower heating cover assembly (20), wherein the upper heating cover assembly and the lower heating cover assembly are in the shape of a circular arc and are symmetrically arranged at the outer side of an iron finishing roller (16); the upper heating cover assembly and the lower heating cover assembly consist of a cover casing (9), an inner clapboard (10), heating coils (12) and an outer clapboard (11); the heating coils (12) are arranged between the inner clapboard and the outer clapboard in a sinusoidal waveform curve; the heating coils can be externally connected with an electromagnetic induction heating controller in an electric cabinet; and an end cover is provided with a sensor for measuring the dynamic temperature of the iron finishing roller, the signal lines of the sensor are connected with a digital display screen and a power adjusting switch in the electric cabinet, and the temperature can be adjusted and controlled by adjusting the amount and the on/off of the current. The invention heats the iron finishing roller by the electromagnetic induction method from the outside, and the heat is not conducted by other materials in the whole heating process, thereby ensuring high heating speed and high thermal efficiency. Meanwhile, the invention has the advantages of good thermal insulation effect, high heat utilization efficiency, less failures and long service life.