A washing machine and a method of controlling the washing machine are provided. According to the washing machine and method of controlling the washing machine, the drum is operated at a first speed so that part of laundry within the drum tumbles and another part of the laundry adheres to the drum. When an unbalance amount of the drum operating at the first speed is a first specific value or less, the speed of the drum is increased to a second speed so that all of the laundry adheres to the drum. When an unbalance amount of the drum detected during the increasing to the second speed is a second specific value or more, the rotation of the drum is decelerated. Accordingly, at a time of a dehydration cycle, stability of the washing machine and laundry balancing can be ensured.