This research aims to found out traditional cost accounting in determining production main price, found out the calculation of Activity Based Costing (ABC) System to determine production main price, and to give input for company's management concerning differences in calculation over product cost using traditional cost accounting and using Activity Based Costing (ABC) System. The method being used in this study would be descriptive study through case study approach the case of PT. Indonesia Pet Bottle Pandaan. The results of this research conducted shows that divergence on calculation and comparison result between traditional cost accounting and Activity Based Costing (ABC) System. Bottle had undercosted or lower product cost charging with 942.506.718,68, while for plastic cup it has overcosted or higher product cost charging with Rp 903.929.466,33. PT Indonesia Pet Bottle should change its traditional cost accounting system by ABC system in determining production main price since information in this system is more accurate to help management in decision making process.