An external disturbances rejection algorithm for flat multi-link manipulator is proposed. Tracking problem is considered as it is generalization of stabilization and regulation problems. Joint coordinates state space is used to simplify mathematical calculations. Electric drives are chosen as joint actuators and their equations are involved into model of the plant. External disturbances and their first and second time derivatives are supposed to be of a certain class and it is the only used limitation. Feedback control law is chosen in the class of discontinuous functions. It is also presumed to be static feedback law as one of the simplest techniques. The efficiency of the proposed algorithm is illustrated by numerical experiments