The present invention relates to a method for determining an imbalance in a drum washing machine. The method comprises the steps of: measuring rotation speeds by rotational sections after a rotation speed of a motor has been increased up to a target rotation speed; comparing the rotation speeds of rotational sections with an allowable range of rotation speeds; and determining whether an imbalance has occurred on the basis of the comparison. Accordingly, the method can improve accuracy for determining whether an imbalance has occurred.