PURPOSE: To reduce a dimension in the longitudinal direction at a low cost by detecting the secondary pressure of an electromagnetic pilot reducing valve acting on the edge surface of a main spool and carrying out the feedback control for position by indirectly detecting the position of the main spool.

CONSTITUTION: The pilot spool 5 of an electromagnetic pilot reducing valve 2 is driven by solenoids 8 and 9 against springs 6 and 7, and the secondary pressure is applied on both the edges of a main spool 15, and the pressure is detected by pressure sensors 18 and 19. The deviation from an instruction signal is calculated by a calculation circuit 21 through a switch 22, having the signals of the pressure sensors 18 and 19 as the position signal of the main spool 15, and the solenoid 8 or 9 is driven through a calculation circuit 23, voltage-electric current converter 28 and a switch 31. Accordingly, the main spool 15 is position-feedback-controlled without using a stroke sensor, and the dimension in the longitudinal direction of a selector valve 3 can be reduced at a low cost.