PURPOSE: To obtain an optical system driving controller for controlling a reverse braking time and always giving the optimum braking force without being influenced by the load fluctuation and motor characteristics, etc., by a simple constitution.

CONSTITUTION: The controller is a device for controlling a DC motor 40 for an optical system which is moved back and forth to be driven, and the controller is provided with a braking mode 51 provided with a regenerative brake and a reverse brake, a switching timing detection sensor 70 for detecting the timing of switching the braking mode 51, a speed level information detecting means 52 for detecting the speed level of the DC motor 40, a reverse braking time controlling means 53 for controlling the reverse braking time T of the DC motor 40 based on the speed level of the DC motor 40 obtained when the switching timing detection sensor 70 is operated.