PURPOSE: To improve the operability of the control system by regulating the moving variable of a cursor in stages in accordance with the revolution of an input device per unit time.

CONSTITUTION: The detection pulses SA, SB of two phases are generated in accordance with the rotation of roller 1a and a detection circuit 3 detects a rotational direction from the phase relation of the detected pulses and outputs control signals SUP, SDW. A counter 7 counts up the number of detection pulses SA, a latch 8 latches a count value (n) at the supplying timing of a pulse PT and a count number deciding circuit 18 converts the output of the latch 8 to a prescribed code signal DT for regulating the moving variable of the cursor and supplies the code signal DT to a remote control code encoder 5. The moving variable of the cursor displayed on a display means is switched in stages in accordance with the rotational frequency of the roller per unit time to display the cursor. Thus, the operability of the control system can be improved.