A tension adjuster for a belt of image forming apparatus is provided. The tension adjuster of the belt includes a tension roller which rotates in contact with an inner surface of the belt. A fixed shaft is disposed a predetermined distance away from the tension roller. A pair of swing arms connect the fixed shaft to a shaft of the tension roller. A tension unit rotates the swing arm on a circumference of the fixed shaft in a first direction so that the tension roller produces a tension on the belt. A tension releasing unit applies torque to the swing arm on the circumference of the fixed shaft in a second direction opposite to the first direction. When the belt rotates, torque generated by the tension unit is greater than the torque generated by the tension releasing unit. When the belt is stopped, the belt is released by the torque of the tension releasing unit.