PURPOSE: To select and take out pressure on the side of low pressure by drilling at least two pieces of flat surfaces from a position facing a second cylinder hole to a rod part on the outer periphery of each land part of a spool and drilling a signal pressure introduction hole opened to the outer periphery of the land part not reaching the flat surface from the end surface of an end rod part in the axial direction.

CONSTITUTION: Flat surfaces 310a, 310b drilled at 180 degrees symmetrical positions in the peripheral direction of land parts 31a, 31b of a spool 3 are formed at a position where their head ends reach a rod part 30 and their rear ends face second cylinder holes 101a, 101b in the neutral state. Additionally, signal pressure introduction holes 33a, 33b deep enough to reach the rear ends of the flat surfaces 310a, 310b are drilled in the axial direction from each of the end surfaces of end part rod parts 32a, 32b. Those signal pressure introduction holes 33a, 33b are opened to the land parts 31a, 31b farther to the rear than the flat surfaces 310a, 310b by a plural number of holes 330a, 330b in the radial direction.