In this paper, we propose a heuristic algorithm based on the Branch-and-Bound Method for solving a Stock Management Probrem. In this algorithm, we divide the problem into small ones and solve them repeatedly. This algorithm achieves considerable speedup over the exact Branch-and-Bound Method. However, we need more speedup to use this in practical situations. To this end, we improve the pruning strategy in the Branch-and-Bound Method. In particular, we define a relaxation problem that can easily be solved by Dynamic Programming and use its solution for pruning. As the result of this, we can get efficient approximate solution in practical time using standard PC.