A spool valve V1 includes a valve element 11 and a cylinder 12 having a bore 12a which accommodates the valve element 11 to be movable in an axial direction. In this spool valve V1, when the valve element 11 in an initial position moves in the axial direction in relation to the cylinder 12, a supply valve port Vi formed between the valve element 11 and the cylinder 12 opens, whereby a working fluid is introduced from a hydraulic pressure source into a hydraulic chamber through the supply valve port Vi. A throttle portion O1 is provided in a fluid channel formed on the hydraulic chamber side of the supply valve port Vi. The throttle portion O1 is configured such that in a throttle valid region which extends from the initial position to a position where the amount of axial movement of the valve element 11 from the initial position becomes equal to a predetermined value, the area of the opening formed between the valve element 11 and the cylinder 12 is constant, and in a throttle invalid region where the amount of axial movement of the valve element 11 exceeds the predetermined value, the area of the opening increases. Thus, it becomes possible to restrain occurrence of oil impact within the hydraulic chamber to which the working fluid is supplied through the spool valve V1.