A servo cylinder comprising: a reducer comprising a reducer main body connected to a motor and a speed reduction output part provided in the reducer main body, the speed reduction output part outputting power from the motor by reducing a rotation speed and increasing torque; a ball screw coupled to the speed reduction output part inside the reducer when one end portion region of the ball screw is inserted into the reducer, the ball screw performing a rotational motion by the speed reduction output part; and a motion conversion output part connected to the ball screw and converting the rotational motion of the ball screw to a linear motion and outputting a converted motion, characterized in that the speed reduction output part comprises a division-type speed reduction output part in which the speed reduction output part is divided into a plurality of parts in a lengthwise direction of the ball screw and the plurality of parts are combined into one body for improvement of contact support area with the ball screw, wherein the division-type speed reduction output part comprises: a first internal reduction output module coupled to internal parts in the reducer main body inside the reducer main body, and to which an end portion of the ball screw is coupled; and a second internal reduction output module coupled to the first internal reduction output module in a thickness direction of the first internal reduction output module, and supporting the one end portion region of the ball screw with the first internal reduction output module. a reducer comprising a reducer main body connected to a motor and a speed reduction output part provided in the reducer main body, the speed reduction output part outputting power from the motor by reducing a rotation speed and increasing torque; a ball screw coupled to the speed reduction output part inside the reducer when one end portion region of the ball screw is inserted into the reducer, the ball screw performing a rotational motion by the speed reduction output part; and a motion conversion output part connected to the ball screw and converting the rotational motion of the ball screw to a linear motion and outputting a converted motion, characterized in that the speed reduction output part comprises a division-type speed reduction output part in which the speed reduction output part is divided into a plurality of parts in a lengthwise direction of the ball screw and the plurality of parts are combined into one body for improvement of contact support area with the ball screw, wherein the division-type speed reduction output part comprises: a first internal reduction output module coupled to internal parts in the reducer main body inside the reducer main body, and to which an end portion of the ball screw is coupled; and a second internal reduction output module coupled to the first internal reduction output module in a thickness direction of the first internal reduction output module, and supporting the one end portion region of the ball screw with the first internal reduction output module. a first internal reduction output module coupled to internal parts in the reducer main body inside the reducer main body, and to which an end portion of the ball screw is coupled; and a second internal reduction output module coupled to the first internal reduction output module in a thickness direction of the first internal reduction output module, and supporting the one end portion region of the ball screw with the first internal reduction output module.