In a valve timing control apparatus, a relative rotational phase between a
drive rotational member rotated with a crankshaft and a driven rotational
member rotated with a camshaft is controlled by a relative rotational
phase-controlling mechanism utilizing a fluid pressure in a fluid
pressure chamber divided by a vane. The relative rotational phase can be
restrained by a locking mechanism at an intermediate phase between most
advanced and most retarded angle phases. As a minimum set torque applied
by a biasing mechanism to the drive rotational member relative to the
driven rotational member, a larger minimum torque required for change
from the most retarded angle phase to the intermediate phase during
cranking, at a temperature before warming up while fluid pressure is
discharged, or at a minimum temperature for relative rotational phase
control while a fluid pressure remains, is selected.