  We obtain a scale-invariant spectrum from the Lee-Wick model in de Sitter
spacetime. This model is a fourth-order scalar theory whose mass parameter is
determined by $M^2=2H^2$. The Harrison-Zel'dovich scale-invariant spectrum is
obtained by Fourier transforming the propagator in position space as well as by
computing the power spectrum directly. It shows clearly that the LW scalar
theory provides a truly scale-invariant spectrum in whole de Sitter, while the
massless scalar propagation in de Sitter shows a scale-invariant spectrum in
the superhorizon region only.
