A motor operated valve comprising: a body (200, 220, 240, 260) including an inlet port (222, 262) through which fluid is introduced from an upstream side, an outlet port (224, 264) through which the fluid is delivered to a downstream side, and a passage through which the inlet port (222, 262) and the outlet port (224, 264) communicate with each other; a valve element to open and close a valve section provided on the passage; a motor including a rotor for driving the valve element in opening and closing directions of the valve section; a shaft coaxially supported by the rotor and movable integrally with the valve element; a feed screw mechanism to convert rotational movement of the rotor into translational movement; and a stopper mechanism to restrict the translational movement of the rotor, wherein the feed screw mechanism includes: a guiding part mounted vertically on the body (200, 240), and including an external thread portion on an outer surface thereof, the shaft being slidably inserted in the guiding part; and a guided part (326, 325) made of a cylindrical member constituting a rotation shaft (326, 325) of the rotor, including an internal thread portion on an inner surface thereof, and mounted around and thus supported by the guiding part, the internal thread portion being engaged with the external thread portion, the stopper mechanism includes: a projection formed on the outer surface of the guiding part; and a stopper member (500, 700) removably mounted on the guided part (326, 325), and including a stopper (506, 706) sticking out radially inward of the inner surface of the guided part (326, 325), and when the valve element is driven by the motor to move in a valve opening direction, the stopper (506, 706) is stopped by the projection in a rotating direction of the rotor, so that the translational movement of the rotor is restricted. a body (200, 220, 240, 260) including an inlet port (222, 262) through which fluid is introduced from an upstream side, an outlet port (224, 264) through which the fluid is delivered to a downstream side, and a passage through which the inlet port (222, 262) and the outlet port (224, 264) communicate with each other; a valve element to open and close a valve section provided on the passage; a motor including a rotor for driving the valve element in opening and closing directions of the valve section; a shaft coaxially supported by the rotor and movable integrally with the valve element; a feed screw mechanism to convert rotational movement of the rotor into translational movement; and a stopper mechanism to restrict the translational movement of the rotor, wherein the feed screw mechanism includes: a guiding part mounted vertically on the body (200, 240), and including an external thread portion on an outer surface thereof, the shaft being slidably inserted in the guiding part; and a guided part (326, 325) made of a cylindrical member constituting a rotation shaft (326, 325) of the rotor, including an internal thread portion on an inner surface thereof, and mounted around and thus supported by the guiding part, the internal thread portion being engaged with the external thread portion, the stopper mechanism includes: a projection formed on the outer surface of the guiding part; and a stopper member (500, 700) removably mounted on the guided part (326, 325), and including a stopper (506, 706) sticking out radially inward of the inner surface of the guided part (326, 325), and when the valve element is driven by the motor to move in a valve opening direction, the stopper (506, 706) is stopped by the projection in a rotating direction of the rotor, so that the translational movement of the rotor is restricted. a guiding part mounted vertically on the body (200, 240), and including an external thread portion on an outer surface thereof, the shaft being slidably inserted in the guiding part; and a guided part (326, 325) made of a cylindrical member constituting a rotation shaft (326, 325) of the rotor, including an internal thread portion on an inner surface thereof, and mounted around and thus supported by the guiding part, the internal thread portion being engaged with the external thread portion, the stopper mechanism includes: a projection formed on the outer surface of the guiding part; and a stopper member (500, 700) removably mounted on the guided part (326, 325), and including a stopper (506, 706) sticking out radially inward of the inner surface of the guided part (326, 325), and when the valve element is driven by the motor to move in a valve opening direction, the stopper (506, 706) is stopped by the projection in a rotating direction of the rotor, so that the translational movement of the rotor is restricted. a projection formed on the outer surface of the guiding part; and a stopper member (500, 700) removably mounted on the guided part (326, 325), and including a stopper (506, 706) sticking out radially inward of the inner surface of the guided part (326, 325), and when the valve element is driven by the motor to move in a valve opening direction, the stopper (506, 706) is stopped by the projection in a rotating direction of the rotor, so that the translational movement of the rotor is restricted.