In practice, the supplier-buyer integration is one of the key principles to business success. Moreover, information sharing is one of the foundations to achieve integration. The information sharing interacts with the supplier's setting price decision and the buyer's ordering quantities. This study develops a JIT single-buyer-single-supplier production inventory model wish pricing and JIT delivery strategy considering multiple-delivery policy, the information sharing investment. This seedy considers the effect of the buyer's ordering quantities on supplier's replenishment policy from supplier's aspect. This buyer-supplier production-inventory model provides an algorithm and derives the optimal production lot size and the shipping quantity when the buyer and the supplier implement the information shoring. A numerical example also presented.