A 4667-second long discharge has been obtained in the ATF torsatron. The total amount of the energy input was 330MJ. The set-up procedures, the control of plasma parameters, and the effect on the wall conditioning for the long pulse discharge are reported in this paper. Fast density feedback control is not useful for a long-pulse operation; control of the neutral pressure on a slower time scale is necessary. Long-pulse discharges are quite effective for wall conditioning. Valuable experiences have been accumulated in the future experiments planned for LHD.