A washing machine includes: a tub; a transmission coil provided in the tub and transmitting power wirelessly; an ammeter measuring an input current value of the transmission coil; a cylindrical drum disposed inside the tub and configured to rotate; a balancer for reducing unbalance during rotation of the drum; and a controller controlling the ammeter and the balancer. The balancer includes: a reception coil provided in the drum and configured to generate power from magnetic field formed by the transmission coil; drive modules driven by power of the reception coil and provided in the drum; and at least one balancing weight that moves along a circumference of the drum by a driving force of each drive module, and changes a center of gravity of the drum. The controller determines a position of the balancing weights based on the input current value when the drum rotates.