Washing machine and control method thereof

A washing machine in which performance of a balancer is improved and a control method thereof. The washing machine includes at least one balancer housing (112) provided with a ring-shaped channel (111), at least one mass body (113) movably disposed in the channel, a confinement unit to confine the at least one mass body to the at least one balancer housing (112) so as to allow the at least one mass body (113) to be rotated under the condition that the at least one mass body is fixed to the at least one balancer housing, an adjustment unit (130) to release confinement of the at least one mass body so as to allow the at least one mass body to descend due to gravity during rotation of the drum, and a control unit to control the adjustment unit so that unbalanced load is offset by the at least one mass body.