A motorized needle valve comprising: a housing formed with a first port communicating with one end portion of a cylindrical communicating hole, and a second port communicating with the other end portion of the communicating hole; a needle valve shaft which is movably mounted in an axial direction in the communicating hole, and which is formed with a tapered portion changed in outer diameter in a direction from one end portion side toward the other end portion side of the communicating hole, and a gap between the tapered portion and a valve seat surface of the communicating hole is changed according to a position thereof in the axial direction; a screw shaft having: a joint portion connected to a main shaft of an electric motor; and a screw portion screwed to one end portion of the needle valve shaft, when the screw shaft is rotated by the electric motor, the needle valve shaft is moved in the axial direction with respect to the screw shaft by the rotation of the screw shaft; a guide provided in the housing, and the guide prevents the needle valve shaft from being rotated around its axis and permits the needle valve shaft to be moved in the axial direction; and a pressure counteracting shaft provided to the other end portion of the needle valve shaft, and provided with a pressure receiving piston which counteracts an axial thrust applied to the needle valve shaft toward the screw shaft by the fluid in one of the first and second ports; a valve body receiving member having a cylindrical portion formed with the communicating hole, the valve body receiving member being mounted in a valve body accommodating hole which is formed between the first port and the second port and makes these ports communicate with each other, and a seal member mounted to the valve body receiving member, the seal member blocking the communication between the first port and the second port, wherein the needle valve shaft has a spacer capable of coming in contact with one end face of the valve body receiving member. a housing formed with a first port communicating with one end portion of a cylindrical communicating hole, and a second port communicating with the other end portion of the communicating hole; a needle valve shaft which is movably mounted in an axial direction in the communicating hole, and which is formed with a tapered portion changed in outer diameter in a direction from one end portion side toward the other end portion side of the communicating hole, and a gap between the tapered portion and a valve seat surface of the communicating hole is changed according to a position thereof in the axial direction; a screw shaft having: a joint portion connected to a main shaft of an electric motor; and a screw portion screwed to one end portion of the needle valve shaft, when the screw shaft is rotated by the electric motor, the needle valve shaft is moved in the axial direction with respect to the screw shaft by the rotation of the screw shaft; a guide provided in the housing, and the guide prevents the needle valve shaft from being rotated around its axis and permits the needle valve shaft to be moved in the axial direction; and a pressure counteracting shaft provided to the other end portion of the needle valve shaft, and provided with a pressure receiving piston which counteracts an axial thrust applied to the needle valve shaft toward the screw shaft by the fluid in one of the first and second ports; a valve body receiving member having a cylindrical portion formed with the communicating hole, the valve body receiving member being mounted in a valve body accommodating hole which is formed between the first port and the second port and makes these ports communicate with each other, and a seal member mounted to the valve body receiving member, the seal member blocking the communication between the first port and the second port, wherein the needle valve shaft has a spacer capable of coming in contact with one end face of the valve body receiving member.