Since many individual production activities release more than one pollutants, policy outcomes of one regulation often complement or contradict those of another regulation. Considering this, an integrated approach to dealing with multiple negative externalities was developed. However, in practice regulating pollutants at a time (i.e., an Ala Carte regulation-approach) rather than an integrated approach is a common regulatory model and, as a result, the inefficiency of regulation arises. The inefficiency even increases as individual environmental policy is implemented with uncoordinated agenda. This paper employs a dynamic game model and explores the issue of optimal regulation for multiple production externalities. In the model, corrective tax rates for two externalities represent the level of regulation. According to findings of our analytical model, regulation level under a comprehensive approach, which simultaneously determines tax rates in year 1, is consistent with Pigouvian rate. Meanwhile, regulation level under an non-integrated approach, which introduce two regulations sequentially, one in year 1 and the other in year 2, deviates from the optimal level: the earlier regulation in year 1 is higher and the latter one in year 2 is lower than those of a comprehensive one. To avoid distortions associated with the sub-optimal level of regulation, our model discourages a use of excessive forward-looking when the level of regulation is made sequentially.