Valve opening/closing timing control device

A valve opening/closing timing control device comprising:

• a driving rotating body that rotates synchronously with a drive shaft of an internal combustion engine;
• a driven rotating body that is disposed coaxially with the driving rotating body and that rotates integrally with a camshaft for opening/closing a valve of the internal combustion engine;
• a lock mechanism that is capable of switching between a locked state in which a relative rotation phase of the driving rotating body and the driven rotating body is kept at a predetermined locked phase and an unlocked state;
• a fluid pressure chamber that is defined between the driving rotating body and the driven rotating body;
• a control valve mechanism that controls supply of a first fluid to an advancing chamber and a retarding chamber, of the fluid pressure chamber, the supply to the advancing chamber causing the relative rotation phase to be displaced in an advance direction, and the supply to the retarding chamber causing the relative rotation phase to be displaced in a retard direction, and that controls supply of the first fluid for controlling the lock mechanism;
• and
• a controller that controls the control valve mechanism,
• wherein the controller performs unlocking at a point in time when a period of time of filling for which either the advancing chamber or the retarding chamber is filled with the first fluid from start-up of the internal combustion engine exceeds a set period of time that is set during the start-up of the internal combustion engine in accordance with the temperature of the first fluid or a second fluid for use in adjustment of the temperature of the internal combustion engine.