An end of a first land has a step difference recessing inward of a radial direction of the first land from the edge portion. The step difference has an end point opposite to the edge portion. A throttle portion protrudes from the start point in an axial direction, and includes an outer-peripheral corner (protrusion round portion) having a curved surface protruding in the axial direction and in the radial direction. When an inlet opening starts to be slightly opened, since a hydraulic fluid is throttled when flowing through a second gate opened between a corner of a sleeve and the protrusion round portion, a rapid increasing of a flow quantity of the hydraulic fluid and an instability of a control of the hydraulic fluid can be suppressed.