A valve opening and closing timing control apparatus includes: a driving side rotator disposed rotatably about a rotation axis and configured to rotate synchronously with a crankshaft; a driven side rotator disposed rotatably about the rotation axis and configured to be rotatable relative to the driving side rotator and to rotate integrally with a valve opening/closing camshaft; a phase adjustment mechanism configured to set a relative rotation phase between the driving side and driven side rotators by a driving force of an electric actuator, a biasing member provided on an outer periphery of a drive shaft to apply a biasing force in a direction such that an inner gear is engaged with a ring gear; and a displacement regulation portion configured to regulate a displacement of the inner gear.