To provide a follow-up control circuit whose configuration is simplified, whose production costs are reduced and which can be miniaturized by a method in which a potential in a point which divides the internal resistance of a DC motor into two parts is used as an equilibrium potential, a temperature compensation circuit with reference to the equilibrium potential is not required and a special power-supply circuit which generates the equilibrium potential is not required.

A potential in the central point which is the center of a coil at a DC servomotor 10, in which inductances La, Lb are equal to each other and in which also internal resistances Ra, Rb are equal to each other is used as an equilibrium potential VDD which is the average potential of potentials Vb, Vg, and the potential is grounded via an electrolytic capacitor C7. Then, the equlibrium potential VDD is supplied to a subtraction circuit 40 and to respective inverting circuits 50, 60, and it controls the DC servomotor 10 in such a way that a feedback amount Vf to be input to a differentiating circuit 30 agrees with a set value Vs. Thereby, a temperature compensation circuit with reference to the equilibrium potential VDD and a special circuit which generates the equilibrium potential VDD are not required, the configuration of a follow-up control circuit is simplified, and the follow-up control circuit can be miniaturized.