A motor-driven valve comprising: a valve shaft provided with a valve element; a guide bush into which the valve shaft is inserted in such a manner as being relatively movable in an axis direction and relatively rotatable about an axis; a valve body that has a valve orifice with a valve seat and to which the guide bush is securely attached; a valve shaft holder externally disposed around the valve shaft; an urging member interposed between the valve shaft and the valve shaft holder and adapted to urge the valve element in a direction in which a valve is closed; a fixation member fixed to the valve shaft and brought into contact with the valve shaft holder with an urging force applied by the urging member so as to couple the valve shaft holder to the valve shaft; a motor having a rotor disposed on an outer periphery of the valve shaft holder and a stator adapted to rotary drive the rotor so as to rotate the valve shaft holder with respect to the guide bush; and a thread feeding mechanism provided between the guide bush and the valve shaft holder and adapted to lift and lower the valve element with respect to the valve seat in accordance with rotary drive of the rotor, wherein the fixation member has a cylindrical fixed portion that is externally fitted and securely attached from a side with respect to the axis direction, to the valve shaft, and a flange extending outward from the fixed portion and brought into contact with the valve shaft holder, and characterized in that the fixed portion has a stepped cylindrical shape with a small-diameter upper portion that is disposed in contact with the valve shaft and a large-diameter lower portion disposed apart from the valve shaft, the large-diameter lower portion being provided with the flange, the small-diameter upper portion being securely attached to the valve shaft from the side with respect to the axis direction, wherein the fixed portion is securely attached to the valve shaft at a plurality of portions in a circumferential direction through welding. a valve shaft provided with a valve element; a guide bush into which the valve shaft is inserted in such a manner as being relatively movable in an axis direction and relatively rotatable about an axis; a valve body that has a valve orifice with a valve seat and to which the guide bush is securely attached; a valve shaft holder externally disposed around the valve shaft; an urging member interposed between the valve shaft and the valve shaft holder and adapted to urge the valve element in a direction in which a valve is closed; a fixation member fixed to the valve shaft and brought into contact with the valve shaft holder with an urging force applied by the urging member so as to couple the valve shaft holder to the valve shaft; a motor having a rotor disposed on an outer periphery of the valve shaft holder and a stator adapted to rotary drive the rotor so as to rotate the valve shaft holder with respect to the guide bush; and a thread feeding mechanism provided between the guide bush and the valve shaft holder and adapted to lift and lower the valve element with respect to the valve seat in accordance with rotary drive of the rotor, wherein the fixation member has a cylindrical fixed portion that is externally fitted and securely attached from a side with respect to the axis direction, to the valve shaft, and a flange extending outward from the fixed portion and brought into contact with the valve shaft holder, and characterized in that the fixed portion has a stepped cylindrical shape with a small-diameter upper portion that is disposed in contact with the valve shaft and a large-diameter lower portion disposed apart from the valve shaft, the large-diameter lower portion being provided with the flange, the small-diameter upper portion being securely attached to the valve shaft from the side with respect to the axis direction, wherein the fixed portion is securely attached to the valve shaft at a plurality of portions in a circumferential direction through welding.