An actuator comprising: a housing; a motor disposed in the housing and including a rotor and a screw, the screw being coupled to a central portion of the rotor; a worm wheel disposed to engage with the screw; and a sealing cover, the housing including a motor accommodation portion having an internal space in which the motor is accommodated, a screw accommodation portion with the screw inserted thereinto, a connecting terminal accommodation portion, and a worm wheel accommodation portion having an accommodation space for the worm wheel, the motor accommodation portion, the screw accommodation portion, the connecting terminal accommodation portion, and the worm wheel accommodation portion being partitioned off from one another, the screw accommodation portion including an inlet connected to the motor accommodation portion and an outlet opposite the motor with respect to the screw and connected to the outside; the connecting terminal accommodation portion being disposed at one lateral side with respect to the screw accommodation portion, and the worm wheel accommodation portion being disposed at the other lateral side with respect to the screw; the sealing cover including a cap; the cap being inserted into the outlet of the screw accommodation portion; the actuator being characterized in that the sealing cover is including a grommet, which is integrally formed with the cap and disposed along the circumference of the cap, and a terminal, which is inserted into the grommet; the terminal including first connecting ends, second connecting ends, and bodies; the bodies connecting the first connecting ends and the second connecting ends, and being disposed along the circumference of the cap, in that the first connecting ends are connected to connecting connectors connected to bus bars in the motor, in that the connecting terminal accommodation portion has an accommodation space in which the said connecting connectors are positioned, and a portion of the connecting terminal accommodation portion is connected to the motor accommodation portion, in that the cap is formed as a cylindrical member to correspond to a shape of the outlet and is formed of an elastic material, and a sealing member is installed along a circumference of the cap, in that the second connecting ends are connected to an external power source, and in that the second connecting ends are positioned opposite the first connecting ends with respect to a virtual diameter line passing through a center of the cap. a housing; a motor disposed in the housing and including a rotor and a screw, the screw being coupled to a central portion of the rotor; a worm wheel disposed to engage with the screw; and a sealing cover, the housing including a motor accommodation portion having an internal space in which the motor is accommodated, a screw accommodation portion with the screw inserted thereinto, a connecting terminal accommodation portion, and a worm wheel accommodation portion having an accommodation space for the worm wheel, the motor accommodation portion, the screw accommodation portion, the connecting terminal accommodation portion, and the worm wheel accommodation portion being partitioned off from one another, the screw accommodation portion including an inlet connected to the motor accommodation portion and an outlet opposite the motor with respect to the screw and connected to the outside; the connecting terminal accommodation portion being disposed at one lateral side with respect to the screw accommodation portion, and the worm wheel accommodation portion being disposed at the other lateral side with respect to the screw; the sealing cover including a cap; the cap being inserted into the outlet of the screw accommodation portion; the actuator being characterized in that the sealing cover is including a grommet, which is integrally formed with the cap and disposed along the circumference of the cap, and a terminal, which is inserted into the grommet; the terminal including first connecting ends, second connecting ends, and bodies; the bodies connecting the first connecting ends and the second connecting ends, and being disposed along the circumference of the cap, in that the first connecting ends are connected to connecting connectors connected to bus bars in the motor, in that the connecting terminal accommodation portion has an accommodation space in which the said connecting connectors are positioned, and a portion of the connecting terminal accommodation portion is connected to the motor accommodation portion, in that the cap is formed as a cylindrical member to correspond to a shape of the outlet and is formed of an elastic material, and a sealing member is installed along a circumference of the cap, in that the second connecting ends are connected to an external power source, and in that the second connecting ends are positioned opposite the first connecting ends with respect to a virtual diameter line passing through a center of the cap.