Demand of any particular products might not be stable, e.g., in the growth stage of the product life cycle where demand of most products might possess increasing functional form. The famous EOQ model is, then, not appropriate in this situation, since it was developed under the assumption of constant demand pattern. The research in this paper is focused on inventory decision problem with non-linear increasing demand pattern and considering shortage, by proposing a heuristic method based on repetitive forward rolling technique for determining the inventory policy for this case, i.e., the replenishment times and shortage points. The proposed technique is developed in such a way that demands during a predefined planning horizon are exactly met. Numerical experiments that are conducted to illustrate the applicability of the proposed technique show that it can provide competitive results when it is compared with other proposed techniques in the past researches.