A valve opening/closing timing control apparatus comprising: a driving side rotational body configured to synchronously rotate with a crankshaft of an internal combustion engine; a driven side rotational body arranged in the driving side rotational body to share a rotational axis therewith and configured to integrally rotate with a camshaft for valve opening/closing of the internal combustion engine; an advanced angle chamber (Ca) and a retarded angle chamber (Cb) defined between the driving side rotational body and the driven side rotational body; a lock mechanism configured to maintain a relative rotational phase between the driving side rotational body and the driven side rotational body by separately biasing a first lock member and a second lock member supported by the driving side rotational body to be respectively engaged with a first recess and a second recess that are formed in the driven side rotational body; and a fluid controller configured to release the locked state by supplying a hydraulic fluid to the first recess and the second recess such that the first lock member and the second lock member are disengaged from the first recess and the second recess, and to control the relative rotational phase by supplying and discharging of the hydraulic fluid with respect to the advanced angle chamber and the retarded angle chamber, characterized in that as a rotational frequency of the driving side rotational body to bring the first and second lock members into a lock released state by a centrifugal force, a first release rotational frequency of the first lock member is set to be lower than a second release rotational frequency of the second lock member, and the fluid controller is configured to control the relative rotational phase to be a phase at which the first recess does not exert a shear force on the first lock member at a time of lock release. a driving side rotational body configured to synchronously rotate with a crankshaft of an internal combustion engine; a driven side rotational body arranged in the driving side rotational body to share a rotational axis therewith and configured to integrally rotate with a camshaft for valve opening/closing of the internal combustion engine; an advanced angle chamber (Ca) and a retarded angle chamber (Cb) defined between the driving side rotational body and the driven side rotational body; a lock mechanism configured to maintain a relative rotational phase between the driving side rotational body and the driven side rotational body by separately biasing a first lock member and a second lock member supported by the driving side rotational body to be respectively engaged with a first recess and a second recess that are formed in the driven side rotational body; and a fluid controller configured to release the locked state by supplying a hydraulic fluid to the first recess and the second recess such that the first lock member and the second lock member are disengaged from the first recess and the second recess, and to control the relative rotational phase by supplying and discharging of the hydraulic fluid with respect to the advanced angle chamber and the retarded angle chamber, characterized in that as a rotational frequency of the driving side rotational body to bring the first and second lock members into a lock released state by a centrifugal force, a first release rotational frequency of the first lock member is set to be lower than a second release rotational frequency of the second lock member, and the fluid controller is configured to control the relative rotational phase to be a phase at which the first recess does not exert a shear force on the first lock member at a time of lock release.