Abstract: A control valve is configured to reduce an axial length of a device as much as possible, thereby improving its mountability. The valve is equipped with a valve body functioning as a cam bolt for connecting a vane rotor to one end of a camshaft, a sleeve fixed to an inner peripheral surface of the valve body, and a spool valve element axially slidably housed in the sleeve for switching between supply and discharge of working fluid to and from each of a phase-retard working chamber and a phase-advance working chamber. The valve body has a male screw part formed on an outer peripheral surface and screwed into a female screw part formed in a cam bolt hole. The position of formation of the male screw part and the position of the spool valve element are arranged to overlap with each other in an axial cross-section.