A servo control device of a DC motor comprising: a DC motor arranged to derive a driven body against a restoring force; a position sensor arranged to detect a moving position of said driven body; a speed detecting section arranged to detect a moving speed of said driven body based on a detection value of the position sensor; a deviation detecting section arranged to detect a deviation of the driven body based on the detection value of the position sensor; a PI control computing section that is arranged to receive the detected moving speed and the detected deviation and a target value predetermined by a target value determining section and is arranged to perform a PI control computation; a steady judgement section that is arranged to judge from the deviation whether conditions of a steady region are held and is arranged to start said PI control computing section by an output signal when the conditions of the steady region are judged to hold to thereby make the PI control computing section execute the PI control computation; and an excitation switching and duty computing section arranged to output a power supply control signal of said DC motor based on an output signal of the PI control computing section when the steady judgement section judges that the conditions of a steady region are held, and arranged to output a previously determined duty signal when the steady judgement section judges that the conditions of a steady region are not held, characterized in that the steady judgement section is arranged to also judge from the moving speed whether conditions of a steady region are held and the detection value from the position sensor is arranged to be read in three times and the second largest detection value is arranged to be adopted. a DC motor arranged to derive a driven body against a restoring force; a position sensor arranged to detect a moving position of said driven body; a speed detecting section arranged to detect a moving speed of said driven body based on a detection value of the position sensor; a deviation detecting section arranged to detect a deviation of the driven body based on the detection value of the position sensor; a PI control computing section that is arranged to receive the detected moving speed and the detected deviation and a target value predetermined by a target value determining section and is arranged to perform a PI control computation; a steady judgement section that is arranged to judge from the deviation whether conditions of a steady region are held and is arranged to start said PI control computing section by an output signal when the conditions of the steady region are judged to hold to thereby make the PI control computing section execute the PI control computation; and an excitation switching and duty computing section arranged to output a power supply control signal of said DC motor based on an output signal of the PI control computing section when the steady judgement section judges that the conditions of a steady region are held, and arranged to output a previously determined duty signal when the steady judgement section judges that the conditions of a steady region are not held, characterized in that