A directional control valve and a valve assembly for incorporating a plurality of control valves is disclosed, in which use of a manifold base, subplates and the like is unnecessary and wherein durability is excellent. A supply port (P) for a pressurized fluid, output ports (A, B) and exhaust ports (EA, EB) which open into a valve hole are defined in a main valve body constituting the directional control valve. The main valve body has linking surfaces thereon for linking together a plurality of control valves in a valve assembly. The supply port (P) and the exhaust ports (EA, EB) penetrate in a direction in which the main valve bodies are linked together at positions deviated from an opening position of the valve hole. In addition, the output ports (A, B) open through output passages on one side surface of the main valve body perpendicular to the linking surfaces. Connecting grooves are defined on upper and lower surfaces of the main valve body. A plurality of the main valve bodies thus constituted are disposed in a linking manner between a pair of end plates, and tie rods are inserted into the connecting grooves so as to clamp the main valve bodies between the end plates.