  We propose a novel mechanism to suppress the isocurvature perturbations of
the QCD axion. The point is that the QCD interactions become strong at an
intermediate or high energy scale in the very early Universe, if the Higgs
field has a sufficiently large expectation value. The effective QCD scale can
be even higher in the presence of extra colored particles. We show that the QCD
axion then becomes so heavy during inflation that its isocurvature
perturbations are significantly suppressed, thereby relaxing the constraint on
the inflation scale.
