To suppress the occurrence of an impact or the like by increasing a damping effect on the axial displacement of a spool.

This spool valve includes a variable restriction mechanism 15 serving as a resistance generating means to provide the damping effect on the axial displacement of the spool 7. The variable restriction mechanism 15 comprises a radial oil path 16 drilled in the spool 7 between the piston sliding hole 7A of the spool 7 and a spring chamber 13, and a piston 17 which is fixed to a cover 6 side and changes the flow path area of the oil path 16 according to the axial displacement of the spool 7. The plunger section 17B of the piston 17 restricts the opening area (flow path area) of the oil path 16 smaller on the end surface 17C side of the plunger section 17B when the spool 7 is positioned at one axial end than when the spool 7 is positioned midway in the axial direction.