This research introduces the sequential bargaining to the standard screening model by allowing the agent to propose new contracts with strategic delay after the rejection of the principal's offer. We have found that if the difference between the types of agent are sufficiently large, the efficient outcome is achieved despite the incomplete information. Otherwise, we have characterized the unique sequential separating equilibrium and the unique simultaneous separating equilibrium with repect to the different parameter values. We've also defined more general "least-cost separating contracts" as well as "bargaining-proof contracts"