A fusing system includes: a fusing unit which comprises a fusing belt which rotates around outer surfaces of at least two rollers which are distanced from each other, and a pressing roller which presses a printing medium together with the fusing belts and fuses an image which is transferred to the printing medium; a heat source which receives power to generate heat, and is mounted inside at least one of the two rollers; a driving source which drives at least one of the two rollers; a sensing unit which senses a surface temperature of the fusing belt; and a control unit which controls the heat source and the driving source so that the fusing belt can be driven when the temperature of the fusing unit increases if a printing order is applied.