Introducing the producer's intertemporal optimizing behavior, we extend the Eckalbar Disequilibrium Macro-Model (1985) and reconsider the dynamic features of the modified model. We concern ourselves with the existence of inventory cycles when the expectations are formed adaptively. The endogenous inventory cycle is detected using the Hopf bifurcation theorem in which a bifurcation parameter is an adaptive coefficient. It is also demonstrated that the generated cycle is subcritical.