A valve timing control apparatus for controlling an opening and closing
timing of a valve of an internal combustion engine includes a driving
side rotational member synchronously rotated with a crankshaft, a driven
side rotational member provided coaxially with the driving side
rotational member and synchronously rotated with a camshaft, a fluid
pressure chamber being separated into an advanced angle chamber and a
retarded angle chamber, a phase control apparatus for displacing a
relative rotational phase between the driving side rotational member and
the driven side rotational member, a locking mechanism having a movable
member, a judging device for judging a supply condition of the operation
fluid relative to the fluid pressure chamber, and a control device for
controlling a rotational speed of the crankshaft.